Cook the lasagne sheets in boiling salted water with oil for 12-15 minutes. Drain, rinse with cold water and place them next to each other on foil. Wash and clean the peppers and tomatoes. Cut the bell peppers into fine slices, the tomatoes into slices.
Grate cheese. Wash the thyme. Pluck the leaves from the stalks. Peel and chop the garlic and fry it in hot fat until transparent. Add milk, sour cream and thyme. Let it boil down. Mix flour with a little cold water.
thicken the sauce with it. Melt 2/3 of the cheese in the sauce. Season the sauce with herbal salt and pepper. Alternately layer lasagne dishes, vegetables and sauce in a greased casserole dish. Finish with tomatoes.
Sprinkle the rest of the cheese over it. Bake in the preheated oven (electric oven: 200 °C/ gas: level 3) for approx. 45 minutes.