Definition: Mochi are sticky rice cakes. Steamed mochi rice (glutinous rice) is pounded to make mochi. Traditionally, wooden mortars and pestles are used to pound mochi rice. Fresh mochi is soft, but it hardens quickly. Prepacked mochi blocks, which are flattened and cut into square pieces or shaped into rounds are available at grocery stores. Mochi get mold easily, so it's best to cook soon. Hard mochi pieces can be grilled, deep-fried, boiled, and more. Cooked mochi is very sticky, so be careful not to choke. It's important to take a small bite at a time.