This dish is so rich it should be a small serving on the side of a light salad.
2 1-pound red-skinned sweet potatoes (yams)
2 tablespoons (packed) golden brown sugar
2 tablespoons (1/4 stick) butter, room temperature
1 12-ounce package wonton wrappers
1 large egg, beaten to blend
1 cup vegetable oil
4 large shallots, cut crosswise into thin rounds, separated into rings
6 tablespoons (3/4 stick) butter
8 large fresh sage leaves, thinly sliced
1/2 teaspoon dried crushed red pepper
1/3 cup pine nuts, toasted
Squeeze of lemon
1/4 cup freshly grated parmesan cheese
Preheat oven to 400°F. Oil rimmed baking sheet. Cut sweet potatoes in half lengthwise; place cut side down on baking sheet. Roast until tender, about 35 minutes; cool. Scoop potato pulp out of skins into small bowl. Spoon 11/3 cups pulp into medium bowl. (Reserve any remaining potato pulp for another use.) Add sugar and butter; mash well. Season filling with salt and pepper.
Line large baking sheet with parchment paper. Place wonton wrappers on work surface. Using pastry brush, brush wrappers with beaten egg. Place 1/2 tablespoon sweet-potato filling in center of each. Fold each wrapper diagonally over filling, forming triangle. Seal edges. Transfer to parchment-lined baking sheet. Let stand at room temperature while preparing fried shallots and sauce. (Can be made up to 5 days ahead. Freeze, then cover and keep frozen. Do not thaw before cooking.)
Meanwhile, working in batches, cook ravioli in pot of boiling salted water until tender, about 3 minutes. Drain well. Add ravioli to pot with butter sauce; toss to coat. Transfer to plates, drizzling any sauce from pot over ravioli. Top with fried shallots and pine nuts; serve immediately.
For fried shallots and sauce: Heat vegetable oil in heavy small saucepan over medium-high heat. Working in 2 batches, fry shallots until crisp and dark brown, about 2 minutes. Using slotted spoon, transfer shallots to paper-towel-lined plate to drain.
Cook butter in large pot over medium heat until beginning to brown, about 3 minutes. Add splash of fresh lemon juice. Remove from heat. Add sage, red pepper, and parmesan cheese.