Put about 1 tablespoon of margarine in a large pan and set the stove to medium heat (Soyola margarine is cholesterol-free and well suited for frying and baking, of course you can also use olive oil or other fat for steaming). Peel the five onions and cut them into very large cubes. Steam with the 250 g diced ham and 1 tablespoon caraway seeds with the lid closed for about 10-13 minutes.
After about 7 or 8 minutes, briefly hold the two slices of toast under water. When they are soaked, squeeze them out well and then fry them in the pan (well distributed - preferably tear into small pieces) for another 4-5 minutes.
In the meantime, lay out the finished puff pastry on a baking sheet (unfortunately one pack is not quite enough and you have to cover half of the second one - but you can freeze the rest and the next time you have the second half available again ).
Now mix the 2 cups of sour cream with the 3 eggs in a bowl, preferably with a whisk. If you like, season with plenty of salt, pepper, fondor (depending on your taste), half a stock cube and more caraway seeds (not too little, otherwise it will taste bland afterwards).
Spread the onion mixture on the puff pastry and pour the sour cream over it.
Now bake the whole thing in the preheated oven at 180 ° C for approx. 45 - 50 minutes.
My information is not exactly accurate in this regard, because we have an ancient oven and everything is a little different (baking times are longer and when we preheat everything turns black).
A Franconian brakeman, also called Federweißer (tastes just as good in other regions) or a cold beer is enough.