01 -
Position a rack in the lower third of the oven and preheat to 375°F.
02 -
Fit the pie crust into a deep 9-inch pie plate. Brush the edge with beaten egg and sprinkle with vanilla or coarse sugar, if desired. Lightly prick the bottom with a fork, line with parchment paper, and fill with pie weights, beans, or rice. Freeze for 10-15 minutes.
03 -
Bake the crust until set, about 20 minutes. Remove pie weights and bake until golden, about 5 minutes. Remove from oven and reduce the oven temperature to 350°F.
04 -
Meanwhile, whisk together the eggs and sugar until smooth. Add the cocoa powder, instant coffee, and salt. Whisk in the melted butter, hazelnut liquor (if using), and vanilla extract. Fold in the chocolate chips. Pour the mixture into the baked crust.
05 -
Bake for 45-55 minutes, until the pie is puffed on top but still slightly wiggly in the center. Remove from the oven and let cool slightly. Serve warm with whipped cream or refrigerate and serve chilled.
06 -
For the whipped cream, whip the heavy cream using an electric mixer until soft peaks form. Add the maple syrup, hazelnut liquor (if using), and vanilla, then whip until combined and fluffy.