Meatball Sandwiches

Ingredients

• 1 egg, lightly beaten -
• 1/2 cup milk -
• 1/2 cup dry bread crumbs -
• 1/4 cup finely chopped onion -
• 1/2 teaspoon salt -
• 1/4 teaspoon garlic powder -
• 1/4 teaspoon pepper -
• 1-1/2 pounds ground beef -
• BARBECUE SAUCE: -
• 1 large onion, chopped -
• 2 tablespoons canola oil -
• 2 garlic cloves, minced -
• 3 cups water -
• 1 can (12 ounces) tomato paste -
• 2 teaspoons salt -
• 1 teaspoon sugar -
• 1 teaspoon dried oregano -
• 1 bay leaf -
• 14 submarine buns (6 inches each), split -
• 1-3/4 cups shredded part-skim mozzarella cheese -