How to Make It
Place the beet in a food processor and pulse until finely chopped. Add the beet greens and pulse until finely chopped.
In a medium saucepan, bring the water and vegetable broth to a simmer. Heat the oil in a large saucepan. Add the onion and cook over moderately high heat, stirring, until softened, 3 minutes. Add the rice and cook, stirring, for 2 minutes. Stir in the beets and beet greens and cook for 1 minute. Add the broth to the large saucepan, 1 cup at a time, and cook over moderate heat, stirring, until the liquid is nearly absorbed between additions, 20 minutes. Add the cheddar; season with salt and pepper. Cook, stirring until the risotto is creamy and thick, 3 minutes longer. Serve in deep bowls, passing the Parmigiano-Reggiano on the side.