Make a kneading dough from the first four ingredients and refrigerate for an hour. Then lay out a 24-inch springform pan with it and pull up the edge two centimeters. It is best to roll out the dough between cling film.
Finely chop the onions (best with a cucumber slicer) and sauté in the butter. Spread on the dough with the cooked ham, smoked pork or meat sausage. Whisk the eggs with the spices and pour over the onions.
Bake the cake in a preheated oven (top / bottom heat) at 200 ° C for 20 minutes.