Combine all of the ingredients for the dough. Let it rest for a few minutes in a warm place and preheat the oven to 180 °C.
Chop bacon and onion and fry in a pan without using any oil or other fats until crunchy and golden. Season mascarpone with pepper (you will most likely not need any salt because of the bacon).
Roll out the dough, put it in your baking dish or pie mold and cover with the mascarpone. Add bacon, onion and sprinkle some peas on top. Bake for approx. 20 minutes.
Tipps
Use green asparagus instead of peas if you like during Spring. If you want the recipe to be even quicker, use store-bought puff pastry for it.