Peel and finely dice the onion and garlic. Fry in hot oil. Add spinach without defrosting and defrost at mild heat in a closed pot for about 10 minutes. Add cream and season with salt and pepper.
Wash and halve the tomatoes. Put spinach with cream and cherry tomatoes in a flat casserole dish. Sprinkle with cheese and bake in a preheated oven (electric range: 200 °C/ gas: level 3) for approx. 10 minutes.