Flank Steak with Caramelized Onions and Balsamic Glaze

Makes 4 servings (serving size: about 3 ounces steak, about 1/4 cup onions, and about 1 tablespoon balsamic glaze)

The reduced balsamic vinegar sauce gives the flank steak a unique flavor that pairs perfectly with the caramelized onions. Both the steak and onions contribute a hefty dose of potassium to this entrée--766 milligrams in each serving. Serve with steamed broccoli or asparagus, and drizzle some of the glaze over the vegetable

2/3 ..................cup balsamic vinegar
1 .....................tablespoon olive oil
6 .....................cups vertically sliced onion (about 1 1/2 pounds)
1/2 ..................teaspoon salt, divided
1 ....................(1-pound) flank steak, trimmed 
1/4 .................teaspoon freshly ground black pepper
1/4 ................teaspoon dried thyme
Cooking spray

1 .       Bring balsamic vinegar to a boil in a small, heavy saucepan. Reduce heat to medium; cook until reduced to 1/4 cup (about 5 minutes). Remove from heat.
2 .      Heat oil in a large nonstick skillet over medium-high heat. Add onion, and sauté 10 minutes or until tender. Sprinkle with 1/4 teaspoon salt; sauté 18 minutes or until onions are golden brown. Remove from heat.
3 .     Preheat broiler.
4 .     Sprinkle steak with remaining 1/4 teaspoon salt, pepper, and thyme. Place steak on a broiler pan coated with cooking spray; broil 6 minutes on each side or until desired degree of doneness. Cutsteak diagonally across grain into thin slices. Serve steak over onions; drizzle with balsamic glaze.
Wine TIP:
Steak and caramelized onions are fabulous partners for numerous red wines. But the balsamic vinegar glaze presents a bit of a challenge since vinegar can make wine taste sharp. These three  varieties  stands up especially well to vinegar: There are  so many . Caberent Sauvignon  ... Pinot Noir  ... Zinfandel  made  by Ferrari -Carano Winery's  in Napa Valley, California, which is dense and lip-smacking .
Heart healthy