Preheat broiler. In a small bowl, mix the first 5 ingredients. Place salmon fillets on a broiler pan, skin side down. Broil 4-6 in. from heat until fish just begins to flake easily with a fork, 15-20 minutes. Brush frequently with onion mixture during the last 5 minutes of cooking.
Nutrition Facts: 1 serving (4 ounces) equals 380 calories, 30 g fat (5 g saturated fat), 67 mg cholesterol, 68 mg sodium, 3 g carbohydrate, 1 g fiber, 23 g protein.