Meatball Sub Grilled Cheese

Ingredients (13)

• 3 Tablespoons olive oil
• 1/2 a large sweet yellow onion, sliced thin
• 2 cloves garlic, minced
• 1/4 teaspoon crushed red pepper flakes, or more if you like more heat
• 1 (28 ounce) can whole tomatoes, with juices
• 1 teaspoon Kosher salt
• 1/2 teaspoon dried oregano
• 2 Tablespoons chopped fresh basil
• 1/2 a bag Farm Rich meatballs (original or Italian)
• 4 Tablespoons butter, softened
• 8 thick slices of crusty Italian bread
• 4 ounces fresh mozzarella, sliced
• 4 slices provolone cheese