Clean the cauliflower and cut into florets. Cook in water with the stock for 15-20 minutes. Cut the drained florets into thick slices and layer them in a casserole dish like a fan. Sprinkle with nutmeg.
Sauté spinach, onions and crushed garlic in a saucepan with butter and leave to cool. Stir in the cream and pour over the cauliflower. Peel, core and dice tomatoes and sprinkle over the casserole. Put the butter flakes on it.
Bake in a preheated oven at 180 degrees for 10 minutes.