1 head cauliflower, florets cut into 1/2-inch pieces, stems chopped fine
3 tablespoons extra-virgin olive oil
Kosher salt and freshly ground pepper
1/2 medium onion, finely chopped
1 1/2 cups short-grain Italian rice (arborio)
1 clove garlic, minced
1/2 cup dry white wine
3 cups low-sodium chicken broth
2 tablespoons unsalted butter
1 1/2 cups Italian fontina cheese, grated
1/2 cup roughly chopped fresh parsley
Position racks in the upper and lower thirds of the oven and preheat to 475 degrees F.
Toss the cauliflower florets with 1 tablespoon olive oil on a baking sheet. Arrange in a single layer and season with salt and pepper to taste. Roast on the upper oven rack, for about 15-20 minutes or until the cauliflower is tender.
Meanwhile, heat the remaining 2 tablespoons olive oil in a Dutch oven over high heat. Add the onion and cauliflower stems and cook, stirring, until the onion is translucent, about 3 minutes. Add the rice and garlic and cook, stirring, 2 minutes. Add the wine and cook, stirring, until evaporated, 1 to 2 minutes. Add the broth, 2 cups water and 1 teaspoon salt; cover and bring to a boil. Transfer the pot to the lower oven rack and bake until the rice is tender, about 15 minutes.
Remove the rice from the oven and add the butter, fontina cheese and parsley, stir until the risotto is creamy, 1 to 2 minutes. Divide among bowls and top with the roasted cauliflower.