In a large bowl or food processor whisk together the flour, cocoa, sugar, baking powder and salt, make a well in the middle (or add to food processor) and add the egg, yolk and butter, mix with a fork or pulse to combine.
When almost combined, move the dough to a lightly floured flat surface and knead gently until combined and smooth. Wrap dough in plastic and refrigerate 30 minutes.
Pre-heat oven to 350° grease and flour an 8 inch pie plate.
Remove from fridge (divide the dough in half, the unused dough may be frozen for future use) and place on a lightly floured surface, gently knead the dough a couple of times to soften it up. Roll out to 1/8" thickness (or a little thicker). Transfer to prepared pie plate, trim the dough of any extra dough then prick the dough all over.
Place a piece of parchment paper on top of the dough and fill it with dried beans, rice or even sugar. Bake for 20 minutes, then remove the paper and weights and bake for another 10-15 minutes or until done. Let cool completely before filling.
PEANUT BUTTER FILLING
In a large bowl beat the mascarpone, peanut butter sugar and vanilla until smooth.
In a large cold bowl (place bowl and beaters in the freezer 20 minutes before using) beat the cream until stiff.
Gently fold the whipped cream into the peanut butter mixture, fold in half the chocolate chips. Pour into the baked crust and sprinkle with the remaining chips. Refrigerate for at least 4 hours or over night. Enjoy!