Grilled Balsamic Steak Skewers – Fustini's Oils & Vinegars

Ingredients

• 1/2 cup Fustini's 18 Year balsamic vinegar
• 2 tablespoons honey
• 1 1/2 tablespoon wholegrain mustard
• 3 cloves garlic, minced
• Kosher salt
• Freshly ground black pepper
• 3/4 pound sirloin steak, cut into 1" pieces
• 1 small red onion, cut into 1" pieces
• 3 cups grape tomatoes
• 1 tablespoon Fustini's Garlic olive oil
• 2 teaspoons freshly chopped rosemary