Peel and finely dice 1 onion. Heat the fat in a pot and fry the onion until transparent. Add the frozen peas, steam for about 1 minute, cover and leave to stand on the switched off hotplate.
In the meantime, wash the herbs, dab dry and chop finely, except for a little to garnish. Cut the ham into cubes. Separate the eggs and mix the egg yolk with quark, milk and semolina. Stir in Parmesan and herbs, except for something to sprinkle, and season vigorously with salt and pepper.
Fold in thawed peas and diced ham, except for something to sprinkle. Beat the egg white until stiff and finally fold in 1 pinch of salt and lemon juice. Fold the egg whites into the quark mixture and place in a greased casserole dish sprinkled with breadcrumbs.
Sprinkle with remaining peas, ham, herbs and parmesan. Bake in the preheated oven 2nd shelf from below (electric oven: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 45 minutes. Cover at the end of the baking time if necessary.
Meanwhile, for the tomato sauce, peel and chop the remaining onions. Wash the tomatoes, dab dry and cut into small cubes. Heat the oil in a pan and fry the onions in it.
Stir in tomato paste and deglaze with broth. Add tomatoes, season with salt, pepper and Italian herbs and let simmer for about 5 minutes. Stir in sauce thickener and bring to the boil again briefly.
Sprinkle the finished casserole with remaining fresh herbs and serve with tomato sauce.