2 tsp. oliv oil
2 1/2 C. thinly sliced sweet onions, such as Vidalia (1 to 2 onions)
1/2 tsp. salt, divided
1/3 C. orange juice
4 tsp. balsamic vinegar
1 tsp. grated orange peel
1 tsp. chopped fresh rosemary
2 tsp. Dijon mustard
1 tsp. honey
4 (4 oz) salmon fillets (1-inch thick), skin removed
1. Heat oven to 425 degrees. Spray 11x7-inch glass baking dish with cooking spray. Heat oil in large nonstick skillet over medium-high heat until hot. Cook onions and 1/4 tsp. of the salt 3 to 4 minutes or until onions begin to turn golden brown, stirring frequently. Reduce heat to medium low; cover and cook 5 minutes or until tender, stirring occasionally.
2. Meanwhile, combine orange juice, vinegar, orange peel and rosemary in small bowl; reserve 2 Tbs. for glaze. Add remaining mixture to onions; cook, uncovered, 2 to 3 minutes or until most of the liquid has evaporated. Whisk mustard and honey into reserved glaze.
3. Spread onion mixture in baking dish; top with salmon. Sprinkle with remaining 1/4 tsp. salt; spoon reserved glaze over salmon. Bake 8 to 10 minutes or until salmon just begins to flake. Serve salmon topped with onion mixture.