Cut the bread into small pieces and fry in the butter like croutons. Then put in a baking dish.
Cut up the cauliflower as desired, cook in boiling water (a little, about 1/4 liter!) For about 5 to 6 minutes until al dente. Catch the cooking water, set aside the cauliflower.
Sear the minced beef, add the crushed garlic, deglaze the cauliflower with the boiling water. Season the sauce with tomato paste, salt, pepper and a pinch of sugar, pour into the baking dish.
Cut the tomatoes into thin slices and place them in the baking dish with the cauliflower. If desired, mix the casserole lightly, then sprinkle with the grated cheese and bake at 200 degrees for about 20 minutes until the cheese is nice and crispy.