Balsamic Steak Skewers If you love grilled red onion and tomato, but feel free to add in whatever you like! Zucchini, mushrooms, or bell peppers would all be great additions.  INGREDIENTS FOR MARINADE 1/2 c. balsamic vinegar 2 tbsp. honey 1 1/2 tbsp. whole-grain mustard 3 cloves garlic, minced Kosher salt Freshly ground black pepper FOR SKEWERS 3/4 lb. sirloin steak, cut [...]