1. Make dough from flour, eggs, butter, sugar, and baking powder. Knead it and leave in a fridge for about an hour.
2. Heat the oven up to 180 C. Grease the baking tin with butter and pour some flour.
3. Separate the dough into two identical pieces. Grate one part into the baking tin. Pour jam on it and spread evenly. The jam can be sour or sweet, depending on your preference. Grate the rest of the dough on top of the jam.
4. Bake the pie for 30-40 minutes. It's just as good cold as it is hot. Enjoy!