meatball subs with caramelized onions

INGREDIENTS

• The baguettes or seeded sandwich rolls you’ll use for your sandwiches (see Note above for how to estimate)
• 2 pound ground meat of your choice (I used pork but have in the past used beef, veal, chicken, turkey or a blend thereof)
• 2 tablespoons chopped parsley
• 1/3 cup finely grated Parmesan or Romano cheese
• 3/4 teaspoon salt
• Pinch of red pepper flakes
• 2 small garlic cloves, minced
• 1 teaspoon onion powder
• 1 teaspoon Worcestershire sauce
• 1 large egg
• Olive oil
• 4 cups prepared tomato sauce (plus extra if you like a lot of extra sauce)
• 2 large yellow onions, thinly sliced
• 1 tablespoon butter
• 1 tablespoon olive oil
• Salt
• 2 cups coarsely shredded Gruyère