Introduction: Inverse Peanut Butter Cup Pie

About: Learn more about me here: or follow me on Twitter (@shesparticular) (if you're into that sort of thing).

In celebration of Pi Day, why not make a yummy treat that incorporates another mathematical favorite - inverse numbers.1

Standard peanut butter cups combine a chocolate exterior with creamy peanut butter insides, and they're fantastic. Though it may be hard to believe, when swapped to produce a peanut buttery crust filled with creamy chocolate filling, they're even more delicious.

1Geek note: The multiplicative inverse of a number (x), also called the reciprocal, is defined as 1/x or x-1

Step 1: You'll Need. . .


For the Crust (amounts can be doubled if desired - this makes approximately 6 mini-pies or one 10 inch tart/pie):
  • 1/2 cup all-purpose flour
  • 1/2 teaspoon baking soda
  • pinch of salt (approximately 1/16 teaspoon)
  • 1/4 cup packed brown sugar
  • 2 tablespoons sugar
  • 4 tablespoons (or 1/4 cup or 1/2 stick) butter
  • 1/2 cup smooth peanut butter, at room temperature
  • 1/2 large egg (beat the egg, then measure out half of it)
  • 1/4 teaspoon pure vanilla extract
For the Filling (you may end up with some extra, but I for one don't mind extra chocolate pudding):
  • 1/8 cup cornstarch
  • 1/4 cup sugar
  • 1/16 teaspoon salt (a large pinch)
  • 1/4 cup milk (2% or whole)
  • 1 cup heavy cream
  • 3 ounces semisweet or dark chocolate, coarsely chopped
  • 1/2 teaspoon pure vanilla extract
Optional Garnish:


For the Crust:
  • large mixing bowl and wooden spoon or hand mixer (food processor can also be used)
  • measuring cups and spoons
  • small tart/pie pans (removable bottoms are strongly suggested) (this is the pan used here) - you can also make a larger pie if desired (crust should be enough for a 10 inch tart/pie pan - one with a removable bottom is suggested)
  • plastic wrap
  • dried beans or pie weights (optional)
  • shot glass or spoon to press dough into pan (optional but suggested)
For the Filling:
  • heavy-bottomed sauce pot
  • silicone spatula
  • whisk (optional - needed if your pudding gets lumpy)
  • fine mesh strainer (optional, also to prevent lumps)
  • measuring cups and spoons

Step 2: Peanut Buttery Crust (part 1)

  1. Stir together the white and brown sugar
  2. Add in butter and peanut butter and mix until combined (it will be very smooth and creamy)
  3. Add the egg and vanilla and stir until well combined
  4. Scrape down the sides of the bowl and add the flour, baking soda, and salt. Mix until just incorporated
  5. Wrap in plastic wrap and refrigerate at least an hour (or up to overnight)

Step 3: Peanut Buttery Crust (part 2)

  1. Press the dough into the tart pan evenly (you'll want a thickness of about 1/8 inch) - using a shot glass or the back of a spoon to press the dough helps create an even surface
  2. If you have any additional dough, it can be formed into cookies (classic peanut butter cookie shape works well) and baked alongside the tart shell
  3. Cover the tart pan with plastic wrap and refrigerate at least 1 hour
  4. Preheat oven to 375 degrees Fahrenheit and bake (with pie weights inside if using) for 9 to 11 minutes, or until golden brown (note: the crust will puff up some at first but will settle towards the end of baking)
  5. Remove from oven and allow to cool fully

Step 4: Chocolaty Goodness

  1. In a saucepan over low heat, combine cornstarch, sugar, and salt
  2. Slowly whisk in the milk and cream, scraping the sides and bottom of the pan with a silicone spatula to incorporate the dry ingredients
  3. Continue stirring over low/medium heat for 15 to 20 minutes until the mixture is thick enough to coat the back of a spoon. If lumps begin to form, use a whisk to beat them out
  4. Once the mixture begins to thicken, add the chocolate and continue stirring for 2 to 4 minutes until the pudding is smooth and thick
  5. Remove from heat and stir in the vanilla
  6. Pass the pudding mixture through a fine mesh strainer (if using) to remove any lumps
  7. Transfer to a bowl and allow to cool fully (refrigerate if desired)

Step 5: Assemble and Enjoy!

  1. Remove tart shells from pan (this is where a pan with removable bottoms comes in handy!)
  2. Spoon the cooled chocolate pudding into the tart shells
  3. Garnish with chopped peanuts or peanut butter powder if desired (I made a stencil using Shrinky Dink plastic - the technique for making the stencil is similar to the one used for the heart stencil explained in steps 3 and 4 of these awesome anatomically correct brownies except it needs to be baked after cutting in order to shrink it (Shrinky Dink plastic shrinks to about a third of its starting size during baking - make sure to factor that in when making your stencil))
  4. Keep refrigerated until ready to serve
  5. Enjoy!
Serious Eats Pi Day Pie Contest

Finalist in the
Serious Eats Pi Day Pie Contest

3rd Epilog Challenge

Participated in the
3rd Epilog Challenge