Adapted from Bon Appetit.
1/4 cup paper-thin onion slices
1/2 cup potatoes, peeled, coarsely grated on large holes of box grater or in processor
1 teaspoon salt
2 tablespoons unsalted butter, 1 melted, 1 not melted
Preheat oven to 350 degrees. Use butter patty to oil a nonstick baking sheet. Place onion in bowl. Toss potatoes with 1 teaspoon salt in bowl. Let stand 5 minutes. Using hands, squeeze out excess liquid from potatoes. Add potatoes and melted butter to onion. Toss to coat.
Divide mixture into 4 small mounds on baking sheet, spacing apart. Bake 15 minutes, then turn mounds over with spatula, pressing down to flatten (cakes will still be soft). Bake until cakes are golden and crisp around edges, about 45 minutes longer.
Serves 1 (makes 4 small cakes)
Per serving: 298 calories; 24 g fat (15 g saturated fat; 72 percent calories from fat); 19 g carbohydrates; 66 mg cholesterol; 1,170 mg sodium; 2 g protein; 2 g fiber.