Caprese Veal Burgers

Ingredients

• 1 cup balsamic vinegar
• 1/2 cup sugar
• Salt
• 1 lb. ground veal
• 1/2 Tablespoon minced garlic
• 1/4 cup minced onion
• 1 Tablespoon chopped parsley
• 1/4 cup flour
• 1 large egg
• 1 teaspoon salt
• 1/2 teaspoon black pepper
• Fresh basil leaves
• Fresh Mozzarella cheese, sliced
• Hamburger buns
• 2 teaspoons butter, melted