Preheat your oven to 180°C.
Unroll your pizza dough.
Spread the tomato sauce over the rolled-out dough.
Finely chop the onion and peppers and sauté them for 10 minutes in olive oil.
Until they are golden.
Slice the mozzarella thinly and place it on your dough.
Slice the tomatoes into rounds and the peppers into strips. Place them on top of the mozzarella. Season with salt and pepper, drizzle generously with olive oil, and add a few handfuls of grated Gruyère cheese.
Bake in the oven for 45 minutes and serve hot.