For the melted onions, first peel and coarsely chop the kilo of onions. Heat some oil in a large! coated pan (I always use a wok, it fits just right) and fry the onions on medium heat. Initially with a lid until the onions are all nice and glazed, then without – there’s a lot of liquid that needs to cook off. When the onions are almost done, deglaze (lighter/darker according to taste) with a shot of rum.
In the meantime, peel and finely chop the remaining onions and garlic cloves for the tomato sauce. Heat a little oil in a saucepan and sauté the onions first, then add the garlic. When the onions are soft and translucent, stir in about 1/2 tube of tomato paste and 1 tablespoon of stock powder and sauté. Then deglaze with the red wine.
Add the canned tomatoes with bay leaf and simmer gently. At the same time, bring water to a boil.
Score the fresh tomatoes crosswise on top, scald them, skin them and cut them into pieces.
Add them to the tomato sauce. Let it simmer well. At the end, season with salt, pepper, sugar, balsamic vinegar and herbs, if desired.
If the sauce becomes too thick, add some more water or wine. Remove the bay leaves before serving. While the tomato sauce and onions are simmering, cook the spaetzle until just cooked and grate the cheese.
When the onions are done, mix them with the spaetzle, half the cheese and half a cup of cream. Season to taste (the spaetzle casserole itself should be slightly sweet, this gives a wonderful contrast to the tomato sauce) and pour into a large baking dish. Cover with the rest of the cheese and cream and bake at 200 degrees for 30 min.
When the casserole bubbles and a nice cheese crust has formed, it is ready. The tomato sauce is served separately on the plate – so you can combine the 2 components as you like.