Peel the garlic and press it through a garlic press. Add to the tomatoes and mix. Season with salt, pepper and herbs of Provence. Peel and slice the onions.
Clean and wash the zucchini and cut them into pencils. Heat 2 tablespoons of olive oil in a frying pan and fry the onions and courgettes for 3-4 minutes. Season with salt and pepper. Slice the cabanossi and rolls.
Put the slices of bread in 4 small gratin dishes. Add the spiced tomato sauce. Spread zucchini, onions and cabanosini slices on top. Drizzle with remaining oil. Grate cheese finely and sprinkle over it.
Bake in the preheated oven (electric oven: 200 °C/ gas: level 3) for 10-15 minutes.