This is my favorite risotto recipe. Easy to modify, but delicious how it is. It's from "The Improvisational Cook" by Sally Schneider.
Heat 6 cups broth and keep it simmering. In a separate, large soup pot, sweat 1/3 cup finely chopped shallots in 2 Tbsp butter. Once golden, add 1.5 cups of arborio rice. Stir the rice continuously for about 5 minutes, until it looks chalky and opaque.
Add 1/3 cup dry sherry. The rice will immediately absorb this. Then add about 1/2 cup of broth at a time, stirring only as much as necessary to incorporate each new dose, and adding the next once the previous has been absorbed. You may not need all the broth; the risotto is done when the rice is tender. At that point, add grated parmesan, another splash of sherry, lemon zest, salt, and pepper (I like Grains of Paradise instead of pepper).