1 1/2 cups mashed sweet potatoes
1/2 cup mascarpone
1/4 cup freshly grated Parmigiano Reggiano
Kosher salt and freshly ground black pepper, to taste
2 to 2 1/2 cups all-purpose flour
1 tbsp olive oil
1/2 cup unsalted butter
2 tablespoons chopped fresh sage leaves
Shaved Parmigiano Reggiano for serving
Heat oven to 400 degrees F. Line a baking sheet with parchment paper.
Pierce potatoes with a fork; place potatoes onto the prepared baking sheet. Place into the oven and bake until tender, about 30 minutes. Let cool completely.
Cut in half; scoop flesh into bowl and mash. Transfer 1 1/2 cups to a large bowl; stir in ricotta, Parmesan, egg, 3/4 teaspoon salt and 1/4 teaspoon pepper. Add flour, 1/2 cup at a time, until a soft dough forms, being careful not to over-knead.
Working on a lightly floured surface, divide dough into 6 equal pieces. Roll each piece into a 20-inch long rope, about 1-inch in diameter, sprinkling with additional flour as needed to prevent sticking. Using a sharp knife, cut each rope into 3/4-inch bite-size pieces; transfer to baking sheet.
Bring a large pot of salted water to a boil; working in 3 batches, cook gnocchi until tender, stirring occasionally, about 4-6 minutes. Drain well and transfer to a clean rimmed baking sheet.
Heat olive oil in a large skillet over medium high heat. Add gnocchi and cook until golden brown and crisp, flipping once, about 2-3 minutes per side; set aside.
Melt butter in the skillet over low heat, 1 tablespoon at a time, until butter starts to foam. Add garlic and sage, and cook, stirring frequently, until fragrant, about 1 minute. Stir in gnocchi and sprinkle with Parmesan.