Flank Steak With Wasabi Rub with sprinkles

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,[...]

1/2 cup shallot , chopped 1/4 cup red wine vinegar 2 tablespoons balsamic vinegar 1 teaspoon ground black pepper , divided 1 (1 lb) flank steak, trimmed 1/4[...]

3 tablespoons unpacked brown sugar 1 1/2 tablespoons balsamic vinegar 3 medium yellow onions , cut in 1/2-inch-thick slices 1 large vidalia onion, cut in[...]