Clean and wash the savoy cabbage and cut into narrow strips. Put in boiling water and cook for 2 minutes, then drain. Line a quiche or springform pan with baking paper or grease it. Preheat the oven to 200 degrees (convection 180 degrees).
Mix the sour cream with the eggs, mustard, caraway seeds and the cheese. Add the savoy cabbage and stir everything well. Pour the mixture onto the puff pastry and bake the quiche for 40 minutes until golden brown.