Peel/clean the vegetables, if necessary blanch or otherwise pre-treat, so that it is faster, for example. Grate the cheese.
In a large gratin dish, mix vegetables, spices, sour cream or crème fraiche, perhaps add a little cheese. Leftovers. Cheese and leftovers. Put the tomatoes on top and put it in the oven, approx. 180 degrees convection or 220-240 degrees without. Alternative: arrange the whole in layers in the form pretty and then cheese over it – looks nicer, but takes longer.
Baking time’ usually about 50-70 min, if everything was pre-cooked / cooked together less. Be careful that the cheese does not burn, then rather put a little bit colder.
Ideal variations can only be found by trial and error! Creativity is very much in demand here (in all points).