Heat the butter and olive oil in a pan. Fry the chopped savoy cabbage and the onions cut into rings until the onions are translucent. Remove from the stove and let cool down a little.
Place the puff pastry in a quiche pan or springform pan, making sure that the edge is covered by the pastry.
Beat the goat cream cheese with the eggs until smooth and season well with salt, pepper and nutmeg.
Place the onion and savoy cabbage mixture in the mold lined with the dough. Spread the cheese and egg mixture on top and sprinkle everything with the grated cheese.
Bake for about 40 minutes and serve warm.
If you don`t like a meat-free version, you can also fry some bacon with the vegetables.