Clean the cauliflower, cut into florets. Cook in salted water until al dente. Pour off and collect some broth.
Fry the minced meat with the onion. Fry the tomato paste briefly. Season and pour in a little vegetable stock. Simmer.
Cut the mushrooms into thin slices, wash the cherry tomatoes.
Put the mince in a baking dish, spread the mushrooms and cherry tomatoes on top. The cauliflower florets on top.
Heat the butter, stir in the flour and pour in the cauliflower stock and a little condensed milk, season and simmer gently. Stir in half of the cheese.
Pour the cheese sauce on the casserole. Sprinkle with the rest of the cheese and bake in the oven at 200 degrees for about 20 minutes.