Start with the pie crust: combine flour, softened butter, egg, sugar, and a pinch of salt in a food processor until you get the texture of a dough.
Form it into a disc, wrap it in plastic, and chill in the refrigerator for at least thirty minutes.
While waiting for the dough, prepare the filling by placing the chopped bacon in a cold pan (or skillet).
Place the skillet over medium-high heat and cook the slices of bacon until crunchy.
Transfer them to a plate and set them aside for later.
Remove some of the bacon fat --- keep about three tablespoons in the pan.
Add the leeks and cumin seeds; cook until the leeks have softened slightly.
Pour the wine and let it evaporate. Taste and adjust the seasoning by adding salt.
Remove from the heat and set aside to cool.
Preheat your oven to 180°C (350°F) and take the dough from the refrigerator.
Unroll the dough and place it in a 9-inch pie tin. Then, use a fork to randomly prick the bottom of the crust.
Cover with an aluminum foil and add some dried beans or rice on top.
Place in the oven for ten to twelve minutes --- then set aside and let cool.
Combine eggs, sour cream, cornstarch, paprika, nutmeg, and salt in a mixing bowl.
Add cheese and the bacon from earlier, then mix everything evenly.
Transfer the leeks into the prebaked crust --- generally about two cups of cooked leeks.
Pour the bacon and sour cream mixture.
Place your German leek pie in the middle of the oven for forty-five to fifty minutes or until the top turns golden.
Set aside to cool, then transfer to a serving plate.
Slice, serve, and enjoy!