1 Cup unbleached all-purpose flour
2 Tablespoons sugar
2 Tablespoons unsweetened cocoa
1/4 Teaspoon salt
2 1/2 Tablespoons vegetable shortening
2 Tablespoons chilled unsalted butter, cut into small pieces
1/4 Cup ice water
3 Tablespoons butter
1/3 Cup semisweet chocolate chips
1 Teaspoon vanilla
4 large egg whites
1 Cup sugar
3/4 Cup unbleached all-purpose flour
1/3 Cup Dutch process cocoa
1/2 Teaspoon baking powder
Dash of salt
To prepare the crust, combine 1 cup flour, 2 tablespoons sugar, 2 tablespoons unsweetened cocoa, and 1/4 teaspoon salt in a food processor; pulse 2 times or until blended. Add shortening and chilled butter; pulse 6 more time or until mixture resembles coarse meal. With the processor on, slowly pour ice water through the food chute, processing just until blended (don’t allow the dough to form a ball); remove from bowl. Gently press mixture into a 4-inch circle; warp in plastic wrap and chill for about 30 minutes.
Preheat oven to 350°F.
Unwrap and place chilled dough on a floured surface. Roll into a 10-inch circle and press into a 9-inch pie plate. Fold edges over and flute.
To prepare the filling, place 3 tablespoons butter and chocolate in a microwave safe bowl. Microwave on high for 30 seconds or until butter and chocolate melt. Stir to combine. Place vanilla and egg whites in the bowl of a mixer and beat at medium speed until foamy. Gradually add 1 cup sugar; beat until soft peaks form, about 2 minutes. Gently fold in melted chocolate and butter mixture.
Combine 3/4 cup flour, 1/3 cup Dutch process cocoa, 1/2 teaspoon baking powder, and a dash of salt in a small bowl. Fold flour mixture into egg white mixture. Pour filling into the prepared crust. Bake at 350°F. for 40 minutes. Cool on a wire rack.