Instructions:

1. Crumble the flour with the butter (or margarine), then knead it together with the other ingredients for the dough. Wrap the dough in plastic wrap and refrigerate for 20 minutes.

2. Roll out the dough on a floured surface to be slightly larger than the pie dish. Press it into the dish. Prick it in several places with a fork and pre-bake in a preheated oven for 10 minutes.

3. Mix all the filling ingredients together and spoon the mixture onto the pre-baked pie crust.

4. Bake until the filling sets and the pie is golden brown.

Suggestions:

In regions where sour cream is not available, it can be substituted with thick Greek yogurt, creme fraiche, or in the last case, with heavy cream. Cottage cheese can be substituted with an equal amount of ricotta cheese.

Variations:

1. Seasonal Fruits: You can add seasonal fruits to the pie. Place the fruit on top of the cottage cheese filling, gently pressing it in, and bake together until done.

2. Jam: If you want to add jam, spread it on the baked pie after it has cooled to at least room temperature.

It is recommended to choose fruits or jams that are slightly acidic to balance the creamy taste of the cottage cheese.