The Official Pie of π Day

Preamble

Do you have socks? Do you like to wear them around the house? I got this pair of wool socks for the winter a couple years back, and let me tell you, they rocked. So snug and comfy I wore them every day. Just get home from work and change into my wool socks. You’d find me still wearing them even as spring rolled around and they weren’t technically all that necessary anymore. Then one day I noticed that π Day was coming soon and figured I should probably bake a pie. Well I made this one, and let me tell you it knocked those socks right off. Also they developed holes from walking around the house in them too much.

It’s a pieced-together Frankenstein of a pie where I use some of Alton Brown’s techniques from both his apple and blueberry pies (drain the apples to pre-shrink them, smash some blueberries to release pectin), a walnut streusel I had atop a restaurant apple crisp once, and the inspiration for the idea from a Betty Crocker pear and mixed berry pie.

Without further ado, I present to you my recipe for the OFFICIAL PIE OF ∏ DAY¹:

Ingredients

Crust

• 6 oz (just under 1¼ cups) all-purpose flour
• 2 oz (¼ cup) butter
• 2 oz (¼ cup) solid fat
• ½ tsp sugar
• ½ tsp salt
• 2 fl. oz water

Filling

• 40 oz (5) apples, mixed
• 18 oz (3 cups) blueberries, fresh or frozen
• 14 oz (1 ½ cups) granulated sugar
• 1.67 oz (⅓ cup) all-purpose flour
• Spices (preferably whole; get enough to yield):
  • 1 tsp ground cinnamon (cassia)
  • ½ tsp ground cloves
  • ½ tsp ground allspice
  • ½ tsp ground cardamom
  • ½ tsp grated nutmeg

Streusel

• 2.5 oz (½ cup) walnuts
• 2.5 oz (⅓ cup) sugar
• 1.25 oz (¼ cup) all-purpose flour
• ½ tsp cinnamon
• 1.5 oz (3 tbsp) melted butter

Equipment

• Oven, stovetop, sharp knife. Because your kitchen is not in ancient Mesopotamia.
• A 9″ pie tin. The pie will go in this.
• A food processor. It’s possible to make a pie without one (used to be commonplace), but it’s more work. Without one of these you’ll need:
  • A hand-held pastry blender to cut fat into the crust dough without melting the butter with your hands. Or in a pinch maybe use a fork?
  • Some way to crush the walnuts. Mortar and pestle? Smash with a rolling pin?
• A spice/coffee grinder, or
  • A mortar and pestle
  • Just buy pre-ground spices
• A rolling pin. I prefer the french style with no handles; it’s dead simple, and will last forever so long as you don’t soak it in water and warp/split it. I’ve also used a wine bottle in a pinch, but they’re not as tall as the crust will be in diameter, so you have to hack it with a 2-pass, go-by-feel kind of method. And use more flour because the glass will stick.
• An accurate scale. Mine lacks really fine precision, so I’m measuring very small amounts volumetrically at the ½-to-1 tsp scale. Above that, and it’s all by weight. In case you don’t have and can’t get a scale, I did include volumetric estimates for everything. But that’s all they are: estimates. Get a bag of flour denser than mine and your dough will be dry and maybe not stick to itself. Sparser and you’ve got too much fat and it gets mushy (this one is more easily fixable: just add more flour).
• Measuring cup. For the water, which can always be measured volumetrically in fluid ounces. And for other ingredients if you lack a scale.
• Some way to crush the blueberries. I used the bottom of a stone mortar inside a Pyrex dish.

Making the Pie (TL;DR version)

1. Refrigerate everything involved with the crust.
2. Core, peel and cut up apples. Coat in sugar. Let drain into a bowl for 90 minutes.
3. Pulse all crust things except water in a food processor until fat is pea-sized. Add water and pulse more. Dump, form into a hockey puck, wrap in plastic, and put in the refrigerator for at least 60 minutes.
4. Pulse all streusel things except butter in a food processor until you almost like the walnut size, then drizzle in butter while processing a little more.
5. Pre-heat oven to 425 ºF (220 ºC, gas mark 7).
6. Set drained apples aside. Smash half of the blueberries. Simmer smashed blueberries, apple juice, sugar, flour, and spices until slightly thickened.
7. Mix apples and whole blueberries in a bowl.
8. Roll out crust, put in parchment-lined pan. Add solid filling. Pour in liquid filling. Sprinkle streusel over top. Put pie in the oven for 40-60 minutes.
9. Cool for at least 4 hours before cutting into.

Making the Pie (Warren Peece version)

A note on blueberries

Believe it or not, I’m actually not the world’s biggest fan of blueberries. They’re ok, I guess, but I won’t generally choose just to eat them straight. Still, when you’ve got a recipe where they work, it pays to use the best you can find. The best tasting of almost any fruit is going to be fresh, in season, and local. And there’s the problem.

Blueberries are a summer fruit, and try as I might I can’t seem to work the numbers to make π Day fall at their optimal time. So you’ve basically got three options:

1. Berries from the southern hemisphere.
2. Local berries grown in a greenhouse with added artificial light.
3. Local berries picked ripe and frozen.

And as I type this I realize the Internet is global and some of you actually live in the southern hemisphere already. Well whoop-de-doo for you. The rest of us must deal with whatever our grocers are selling. For me that meant blueberries imported from Chile. Nothing particularly wrong with the other options either, flavor-wise. If you’re trying to save the planet and buy ethically? Simply compare the energy consumption of shipping from Chile, heating and lighting an artificial environment for off-season growing months, or powering a freezer for the same amount of time, amortizing the energy expenditure over the amount of food produced/delivered. I have not done the math.

Prepare the apples

A lot of baking requires precision, as differentiated against normal cooking where you eyeball this, estimate that, and otherwise go all Jackson Pollack on it. This here with the apples is your chance to be creative with your pie. This time around I decided on relatively large chunks to yield a pie with a firm bite to its contents. If you want your pie softer, you can cut into smaller chunks, slice the apples thin, or come up with your own thing. You also have the option (I declined it this time) of pre-cooking the filling to soften it before baking. We’ll address that when it’s time.

1. Core, peel and section the apples. Here’s my method:
   1. Slice an apple in half vertically, bisecting the core.
   2. A melon baller is super convenient for coring apples.
   3. Further divide the apple into ⅛ths.
   4. Peel the slices by placing them skin side down and rolling them under a sharp knife.
   5. Divide each slice into 3 equal chunks, yielding 24 chunks per apple.
   6. Repeat for each apple.
2. Coat apple chunks in about ⅓ of the sugar (about ½ cup). Precision is wasted here, just eyeball it.
3. Place coated chunks in a strainer or colander over a bowl.
4. Let them drain for an hour and a half.

Make the dough for the crust

You’re going to need to decide on your choice of fat. What we’re really going for here is a pure fat that is flavor-neutral and solid at room temperature. This is where we’ll get the crust to be flakey. Basically little balls of this fat will be embedded in the dough and fry it crisp from the inside. You can sub in butter here — and a lot of pie crust recipes do — but the crust will not be flakey. Butter has a different purpose, that being to melt below body temperature. It literally melts in your mouth, and you want that too, which is why there are also 2 ounces of butter, but butter is only 80% fat, and will not fry the dough due to the 15% water (the rest is solids, which are mostly what give the butter its distinctive flavor).

My go-to here is lard. Lard is awesome. People actually used to spread lard on their bread, the way we do with butter now, but it got a bad rap somewhere along the way and now is hard to find. My local grocery store does not carry it. I considered rendering some fat out of bacon, but that’s going to hold onto some smoke and sodium nitrite flavor, no matter how carefully you render. Another option is shortening. This is a pure, tasteless fat engineered to be exactly what we need for this kind of pastry work. Unfortunately, the partial hydrogenation (i.e. trans fats) used to keep it shelf stable and solid at room temperature has fallen out of favor among the health conscious, due to heart concerns. Still, either it or an all-butter crust remain the only options for vegetarians hoping to make pie.

What I decided to use — and availability of this may simply be peculiar to my grocery — is duck fat. If you’re like most people, you probably have some left over from the last time you confited duck legs, but don’t use that batch. It’ll carry over the garlic and herb flavors you infused it with. Pure rendered duck fat though works perfectly. You’ll need to do a few things:

1. Refrigerate the 2 oz water.
2. Combine the flour, salt, and sugar in a food processor.
3. Cut the butter and pure fat into ½” chunks. Since the duck fat came in a tub, I used a ½ teaspoon to scoop out little spheres of it. Measure by weight, and add to the food processor.
4. Put the whole food processor container/bowl part in the refrigerator, blade and all, for about 15 minutes.
5. Reassemble your food processor and start pulsing to combine. Continue to pulse until the fat is broken up into little balls about the size of a pea.
6. Dump in the water all at once and pulse a few more times to combine. Don’t overdo it or you’ll start to develop the gluten in the flour and make the crust tougher than it needs to be. It should still look crumbly and not have formed a dough yet.
7. Dump out onto a lightly floured surface.
8. Quickly form into a hockey puck. Press together firmly enough to shape into a solid mass, but stop short of touching it so much that you start to melt the butter.
9. Wrap tightly in plastic wrap and put in the refrigerator for an hour.

Prepare the spices (optional)

I marked this as optional, but you should really consider it. In addition to just plain smelling awesome, whole spices keep a lot longer without losing potency. I’ve had black peppercorns I forgot about for years, ground them fresh, and it’s simply beautiful, while the pre-ground stuff smells like nothing after only a few months. If you’re going with pre-ground, you can skip this part, but at least try to buy new spices regularly.

1. Measure out enough of your spice to result in the right amount after grinding. This is tricky, and until you have some experience you’ll probably just need to start small and add to the grinder more and more until you have enough. I used:
   • One 3″ stick of cinnamon.
   • One nutmeg seed.
   • One tsp cardamom seeds (if you buy pods, open them and get the seeds out).
   • One heaping teaspoon dried allspice berries.
   • One very heaping teaspoon cloves, like spilling over.
   • In all cases I had a little left over. Cost of doing business.
2. For the cinnamon:
   1. Use a knife to crack into small chunks. A mortar and pestle is also probably good for this, but the buggers are tough. You’ll have to whack at them and pieces will fly everywhere no matter what method you use. Just so you know.
   2. Put the pieces into a grinder and grind away.
   3. Measure out 1 tsp for the filling and ½ tsp for the streusel.
   4. Dump any leftovers.
3. For the nutmeg: grate out ½ tsp
4. $([cardamom, allspice, cloves]).each(function(spice) {
   1. Load spice into the grinder and grind.
   2. Measure out ½ tsp and dump any leftovers.
5. });
6. Combine 1 tsp cinnamon and the rest of the spices in one bowl, the rest (½ tsp) of the cinnamon in another. Check out the smell. I know, right?

Make the streusel

1. Put the walnuts, sugar, flour, and cinnamon in the (cleaned) food processor and pulse to approach the size you want the nuts to end up at. Leave them a little bigger though. (For illustrative purposes in the pictures below, I processed the walnuts by themselves first, then added the other ingredients)
2. Run the processor as you drizzle in the melted butter. Stop when you’re happy with the size of your streusel.

Make the filling

1. When the apples have drained for 90 minutes, set them aside.
2. Smash half (9 oz, 1½ cups) of the blueberries to release their juice (and pectin, which is why we don’t need to add any pectin or gelatin to the pie). The picture below shows that I smashed mine with the very same stone mortar I did not use for the spices.
3. Add the smashed blueberries and all their juice to a sauce pan, along with the drained juice from the apples, the flour, spices, and the rest of the sugar. Simmer for a few minutes, stirring to avoid burning the sugar, until the solution has thickened up a bit. OPTIONAL: throw in the apples at this point to precook them for a softer final texture.
4. Mix together the solids (apples and whole blueberries) in a bowl. The same one you used to catch the juice is fine, no need even to wash it.

Assemble the pie

1. Line the bottom of your 9″ pie tin with parchment, for easy removal of the pie later.
   1. Fold up a piece of parchment a whole bunch of times, radially from the center.
   2. Cut it at a length equal to the radius of the bottom of the tin.
   3. Unfold and behold!
2. It’s dough time
   1. Unwrap the dough and place on a floured work surface. Go ahead and add more flour to the top.
   2. Roll out the dough, adding flour as necessary and flipping regularly to avoid sticking. Be sure to roll in multiple directions.
   3. Cut off weird edge protuberances and use them to fill in weird edge gaps.
   4. Forget about thickness. Most recipes say to roll out until it’s 1/x” thick. We want to use the dough we’ve made, so roll out just until it’s a circle the size you’re going to need to fill up the pan, maybe a bit bigger.
   5. Put crust in pan. Cut around the edge with a knife to make a nice neat circle.
3. Transfer the filling to the pan. Start with the solids to make a nice pie shape, higher in the middle. Then pour in the liquid to fill in the spaces. If you really cooked it down, it may all fit. Mine did not, and we used the leftovers (sauce included!) to top some french vanilla ice cream.
4. Sprinkle the streusel on top. Try to keep it uncompacted by handling it gently. A nice, even layer.

Bake the Pie

1. Place the pie in the preheated oven in the middle rack, on a sheet pan small enough to allow air flow around it (I use a half-sheet in a 36″ oven).
2. Cook for 40-60 minutes, depending on your oven. I set my alarm for 40 minutes, then checked back every 5. It was done at 50.
3. We’re using a porous crust. Apple-blueberry syrup will bubble out and make a mess. This is a feature, not a bug.
4. Let cool for at least 4 hours. No harm in using the refrigerator to help out, but if you don’t get it thoroughly cool, the inside will remain runny.

1. Official with respect to the “π Day” song by Brian Gray. Author assumes no authority to claim official status with respect to the holiday itself. ↩