Risotto with Carrots Four Ways

Name: Risotto with Carrots Four Ways
Ingredients: 7 carrots, peeled; 1 tablespoon unsalted butter; Salt; Pinch of sugar; Olive oil; 1 onion, diced; 3 cloves garlic, minced; 2 cups arborio rice; 6 cups chicken or vegetable broth; 1/2 cup mascarpone cheese; 1/4 cup grated Parmesan cheese; Chopped parsley, for garnish