Sauté the onions, add the rice, deglaze with the broth and continue to cook. About 10 minutes before the rice is cooked, add one tablespoon of tomato paste, keep cooking.
After 16/18 minutes of cooking, finalize the risotto by adding butter and the parmigiano reggiano. Try to obtain a creamy and beautifully red colored risotto. Serve the risotto with the buffalo mozzarella or the burrata, that you have previously seasoned with olive oil, salt and fresh basil, at the center of the plate.