Sweet Potato Gnocchi with Brown Butter and Sage

Name: Sweet Potato Gnocchi with Brown Butter and Sage
Ingredients: 2 1-pound red-skinned sweet potatoes (yams), rinsed, patted dry, pierced all over with fork; 1 12-ounce container fresh ricotta cheese, drained in sieve 2 hours; 1 cup finely grated Parmesan cheese (about 3 ounces); 2 tablespoons (packed) golden brown sugar; 2 teaspoons plus 2 tablespoons salt; 1/2 teaspoon freshly ground nutmeg; 2 3/4 cups (about) all purpose flour; 1 cup (2 sticks) unsalted butter; 6 tablespoons chopped fresh sage plus whole leaves for garnish