The main ingredient in a mushroom risotto is Arborio rice, a short-grain rice that is high in starch. This type of rice is crucial for achieving the creamy texture characteristic of risotto. During the cooking process, Arborio rice absorbs liquids like broth gradually, allowing the outer starch to gelatinize and create a rich, velvety consistency. To make mushroom risotto, the rice is typically sautéed with aromatics like onions and garlic, then slowly cooked while gradually adding broth. Fresh or sautéed mushrooms can be incorporated for flavor, alongside cheese or herbs, to enhance the dish's richness and earthiness.