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Hooray! - The Perfect Pie to Celebrate Pi Day

Venn Pieagram Pie for Pi Day on

Yup, for those of you not in-the-know, this is a real thing.  Celebrated March 14th, Pi Day is often marked by pie baking, pie eating contests, discussing the merits of the number π, and so forth.  Which brings me to my story…

Recently, my husband told me about a three-in-one pie he had heard about, made by intersecting two pie tins.   He then challenged me to create such a spectacle.  Because I’m a sucker for a good challenge (and a good pie), I gladly accepted. While I didn’t find good instruction online to making such a pie, I’ve documented the steps I took below.  It looks complicated, but is so amazingly easy – the perfect combination! It’s also a delicious way to teach your kids about Pi in all it’s 3.14159265359 glory.

I’ve since learned that this marvel of a 3-in-1 pie dessert is sometimes referred to as a ‘Venn Pieagram’.  (Get it!?)

Venn Pieagram Pie for Pi Day on

And here’s how you make one…

For one Venn Pieagram pie, you will need:

  • Two foil pie pans
  • A serrated knife and kitchen scissors
  • Three pie fillings (you will only use approximately half of each)
  • Three pie crusts (two for the bottom crusts and one for the top crusts)

Venn Pieagram Pie for Pi Day on


– For my pie, I created a double-crust apple pie, lattice cherry pie and one pumpkin pie.  If you decide you want more than one double-crust pie, you may need to use additional piecrusts).

– Making this 3-in-1 pie requires three different pie fillings.  If you’re using your typical quantity of filling (your favorite homemade filling recipe or a can of store-bought filling), you will discover that it only takes about half of the amount you would use for a full pie (for each flavor).  For this reason, I suggest you make two ‘venn pieagram’ pies at a time.  That’s one to share, and one to devour yourself!

1.  Modify Your Pan

  • First, start with two foil pie pans.   About 1/3 of the way around one of the tins, use a serrated knife to cut through the crease of the pan (where the floor of the pan meets the wall).   Use a kitchen scissors to then cut the wall of the pan vertically (from the floor to the rim) on both sides of the cut – (careful not to cut through the rim!).
  • Take your second pan (untouched) and slip it into the pan you just cut to create a pan of two intersected circles (often referred to as a venn diagram).

Venn Pieagram Pie for Pi Day on

2.  Layout your bottom crust

  • Use your first round of pie crust to cover the bottom of both one outer pie AND the center pie.  (You will need to work the crust well into the cavern of the pan beneath the rim of the inner pie, ensuring that it is pressed up against all walls.)  You will discover that there is excess crust at the top and bottom points of the center pie, so simply use a kitchen scissors to remove any excess and use your fingers to pinch the dough back together.
  • Add the second round of piecrust to the remaining outer pie.  Again, ensure that it is pushed up against all walls of your moon-shaped pie pan.  Where the crust meets the edge of the crust of the center pie, press the dough together and trim off the excess.  (I find it easiest to lay the crust gently in the pan and gauge approximately where the excess dough will need to be cut, score that area with a knife and cut off the excess with my kitchen scissors).

You should now have your bottom crusts applied to the entire pan.  (The hard part is done!)

Venn Pieagram Pie for Pi Day on

3.  Add fillings and top crusts

  • Add each filling one-at-a-time, starting with fillings that will require a top-crust. Use the third pie crust round to top the pies.  You can use solid top-crusts, lattice, or any others you like.


– Hold off on adding fillings that do not require a top crust (such as Pumpkin Pie filling) until last, so it doesn’t spill as you add the top crusts to the other pies.

– Be sure to pierce holes in the solid top-crusts to allow steam to escape.

– Once your top crusts are added, finish the outer edges of the pie dough, including the edges of the center pie – at all points where the piecrusts meet.

Venn Pieagram Pie for Pi Day on

I used the prongs of a fork to crimp the edges, then trim flush to the edge of the trim with a paring knife.   Why?  Because it’s fast, and because that’s how my mother did it.  If you like a fancier pinched-edge finish, knock yourself out!

  • Add any remaining fillings that do not require a top crust.

Venn Pieagram Pie for Pi Day on

4.  Finishing details

  • Finish the top of your crusts as necessary (this will vary by the type of pies your making).  For me, this simply included brushing the top of my apple pie with milk and sprinkling with cinnamon.

Venn Pieagram Pie for Pi Day on

5.  Bake

  • Gently slide your completed 3-in-1 pie onto a flat cookie sheet.  (An uncooked 3-in-1 pie is flimsy and this makes it easy to get it into and out of the oven).
  • Use strips of tinfoil to carefully cover the edges of the 3-in-1 pie to prevent burning during baking.
  • Bake your pies according to the instruction of the pie you’re making that requires the longest baking time.  Pie fillings are generally pretty forgiving and most can endure a little over-baking, so go for the longest baking time necessary, but be sure to check in on your pie periodically. (For my pie, I baked it according to the Pumpkin Pie filling instructions).
  • Let your pie cool on the cookie sheet, and viola!  A pie spectacle your friends and family will be Instagraming for days!


And there you have it – the Venn Pieagram!

Check out this super-fast time-lapse video to see how simple it really is.


A native of the Midwest, Bridget Charon is a freelance digital producer, a ‘maker’, wife, and mother of two small children (not necessarily in that order).   She is a novice cook, a baking enthusiast, a humorous cynic, and a dreamer at large. Bridget holds firm to the belief that consolation baking is the best way to help a preschooler through a bad day.  (Because, hey – one of the best parts of life is getting to lick the beaters).