Ingredients

• 2 medium onions, quartered lengthwise
• 3 tablespoons vegetable oil
• 1 teaspoon caraway seeds
• 1 Turkish bay leaf or 1/2 California
• 1 (14- to 15-ounce) can diced tomatoes
• 1 cup reduced-sodium chicken broth
• 1 teaspoon sugar
• 1/3 cup chopped dill
• 24 frozen potato-Cheddar pierogies (preferably Mrs. T's; not thawed)
• Accompaniment: sour cream

Instructions

1. Bring 4 quarts water to a boil in a large pot, then reduce heat and keep at a bare simmer, covered, until ready to use.
2. While water comes to a boil, thinly slice onions in a food processor fitted with slicing disk. Heat oil in a 12-inch heavy skillet over medium-high heat until it shimmers, then cook caraway seeds and bay leaf, stirring, until fragrant, about 30 seconds. Add onions and cook, stirring occasionally, until golden, 8 to 10 minutes. Increase heat to high and cook, stirring frequently, until onions are dark brown and just beginning to char, about 2 minutes. Carefully stir in tomatoes with their juice, broth, sugar, 3/4 teaspoon salt, and 1/2 teaspoon pepper (juices may spatter) and simmer 3 minutes. Stir in dill and discard bay leaf.
3. Boil pierogies according to package directions (5 to 7 minutes), then drain. Serve topped with tomato sauce.