How to Make It
Preheat the oven to 350°. In a saucepan, combine the maple syrup, tomato sauce, vinegar, lemon juice, brown sugar, garlic, ginger and 1 teaspoon each of salt and pepper; bring to a boil. Simmer over low heat for 15 minutes.
Meanwhile, set each rack of ribs on a large rimmed baking sheet, meaty side up, and season all over with salt and pepper. Roast the ribs for 30 minutes, shifting the pans from top to bottom halfway through cooking.
Brush the ribs with some of the sauce and roast for about 1 1/2 hours longer, brushing with the sauce every 15 minutes and shifting the pans occasionally. If the pan juices begin to burn, add a few tablespoons of water to the pans and scrape up any caramelized drippings; baste the ribs with the drippings. Remove from the oven.
Preheat the broiler and position a rack 8 inches from the heat source. Put both racks of ribs on 1 baking sheet, meaty side down, and brush with the sauce. Broil the ribs for 2 to 3 minutes, until glazed and lightly crusty. Turn the ribs, brush with any remaining sauce and broil for about 3 minutes, or until glazed and crusty; transfer to a work surface. Cut in between the bones, mound the ribs on a platter and serve.