Gingersnaps add an unexpected zing and are a great foil to the richness of this chocolatey pie. Sub in gluten-free graham crackers if you prefer.
- 1 8-oz. package gluten-free gingersnaps (about 36 cookies; preferably Mi-Del brand)
- 6 tablespoons unsalted butter, melted, cooled slightly
Cream Filling and Assembly
- 6 ounces semisweet chocolate, chopped, or 1½ cups chocolate chips
- 1½ tablespoons unsalted butter
- 1 teaspoon vanilla extract
- ¼ teaspoon instant espresso powder
- ¾ cup chilled heavy cream
- Chocolate shavings (for serving)
Place a rack in middle of oven and preheat to 350°. Pulse gingersnaps in a food processor until very fine crumbs form. Drizzle butter over crumbs and add sugar; pulse until mixture is the consistency of wet sand. Transfer mixture to a 9" pie dish. Using a measuring cup, press firmly onto bottom and up sides of pie dish. Bake until crust is dry and set, 10–12 minutes. Transfer to a wire rack and let cool.
Whisk egg yolks, cornstarch, salt, and 1/3 cup sugar in a medium saucepan until smooth and pale. Whisking constantly, gradually add milk. Bring to a boil over medium heat. Reduce heat and simmer, whisking constantly, until custard is thickened and whisk leaves a trail, about 2 minutes. Remove from heat and add chocolate, butter, vanilla, and espresso powder and whisk until chocolate and butter are melted and mixture is completely smooth.
Strain custard through a fine-mesh sieve into a medium bowl, pressing it through with a rubber spatula. Spoon into chilled crust and cover with plastic wrap, pressing directly onto surface. Chill until set, at least 2 hours.
Just before serving, beat cream and remaining 1 Tbsp. sugar in a medium bowl to stiff peaks. Spread whipped cream over pie, swirling decoratively; top with chocolate shavings.
DO AHEAD: Pie without whipped cream can be made 1 day ahead. Keep chilled.