Instructions

To make the crust:

1. Preheat the oven to 350F and line a large cookie sheet with parchment paper.
2. Using a hand or stand mixer with the paddle attachment, mix together the butter and sugars. Mix on medium-high speed for 2-3 minutes until fluffy and pale.
3. Scrape down the sides of the bowl and mix in the egg yolk on low speed. Increase to medium-high and beat for 1-2 minutes or until the sugar is fully dissolved and the mixture is pale yellow.
4. On low speed, add in the flour, baking powder, baking soda, salt, and chocolate chips. Mix until it just comes together.
5. As best as you can, spread the dough in an even layer on the parchment paper. It should be about 1/4 inch thick.  It won’t cover the entire pan. It’ll just look like a big cookie blob.
6. Bake for 15 minutes or until it has golden brown edges and a dull top. Cool completely before using. If you’re making it ahead, you can crumble it up into an air-tight container and store in the fridge. It will keep up to 1 week.
7. After the cookie has cooled, crumble it up into a food processor along with the brown sugar and salt. Pulse until it resembles wet sand. In Christina’s recipe, she says that if you don’t have a food processor, to “fake it till you make it and crumble the oat cookie diligently with your hands.”
8. Transfer the crumbs to a bowl and add the melted butter. Feel free to use your hands to fully incorporate it. It should be wet enough to where it can form a ball. If it doesn’t, add 1 to 1 1/2 tablespoons of butter at a time until you get there.
9. Press the crust firmly into your 10 inch pie pan to make sure the bottom and edges are covered. 

To make the filling:

1. Combine the sugar, brown sugar, ovaltine, cocoa powder, and salt in the bowl of a stand mixer fitted with the paddle attachment and mix on low speed until evenly blended.
2. Add the melted butter and paddle for 2 to 3 minutes until all the dry ingredients are moist.
3. Add the heavy cream and vanilla and continue mixing on low for 2 to 3 minutes until any white streaks from the cream have completely disappeared into the mixture. Scrape down the sides of the bowl with a spatula.
4. Add the egg yolks, paddling them into the mixture just to combine; be careful not to aerate the mixture, but be certain the mixture is glossy and homogeneous. Mix on low speed until it is.
5. Use the filling right away, or store it in an airtight container in the fridge for up to 1 week.

Bake the pie:

1. Pour the filling into the prepared pie crust. It should be 3/4 of the way full.
2. Bake at 350 degrees for 15 minutes. Then open the oven door and reduce your temperature to 325F. When your oven reaches that temperature, close the door and bake the pie for another 5 minutes. It should be a little jiggly in the very center of the pie but not on the edges. If it’s still too jiggly, leave them in for an additional 5 minutes.
3. Take the pie out of the oven and transfer to a cooking rack. Then freeze your pie for at least 3 hours or overnight. This is what gives you that dense center. Transfer to the refrigerator to thaw for at least 1 hour before serving. Serve cold.
4. Dust your mixture of powdered sugar and cocoa powder all over the top.