- 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
- Line large baking sheet with parchment paper. Place sweet potatoes on plate; microwave on high until tender, about 5 minutes per side. Cut in half and cool. Scrape sweet potato flesh into medium bowl and mash; transfer 3 cups to large bowl. Add ricotta cheese; blend well. Add Parmesan cheese, brown sugar, 2 teaspoons salt, and nutmeg; mash to blend. Mix in flour, about 1/2 cup at a time, until soft dough forms.
- Turn dough out onto floured surface; divide into 6 equal pieces. Rolling between palms and floured work surface, form each piece into 20-inch-long rope (about 1 inch in diameter), sprinkling with flour as needed if sticky. Cut each rope into 20 pieces. Roll each piece over tines of fork to indent. Transfer to baking sheet.
- Bring large pot of water to boil; add 2 tablespoons salt and return to boil. Working in batches, boil gnocchi until tender, 5 to 6 minutes. Transfer gnocchi to clean rimmed baking sheet. Cool completely. (Can be made 4 hours ahead. Let stand at room temperature.)
- Preheat oven to 300°F. Melt butter in heavy large saucepan over medium-high heat. Cook until butter solids are brown and have toasty aroma, swirling pan occasionally, about 5 minutes.
- Add chopped sage (mixture will bubble up). Turn off heat. Season sage butter generously with salt and pepper.
- Transfer half of sage butter to large skillet set over medium-high heat. Add half of gnocchi. Sauté until gnocchi are heated through, about 6 minutes. Empty skillet onto rimmed baking sheet; place in oven to keep warm. Repeat with remaining sage butter and gnocchi.
- Divide gnocchi and sauce among shallow bowls. Garnish with sage leaves.