Wash and chop the spinach, onions and press the garlic.
Heat the oil in a pot, braise the onions and garlic in it, add the spinach and saute until the spinach changes color slightly.
Remove the lid and wait for the water to evaporate.
Add the cream, season with salt, black pepper, stir well.
Transfer everything to an oven dish, sprinkle with grated cheese and crisp in a preheated 392°F (200 °C) oven until the cheese melts.