Meatball sub

Preheat the oven to 350 degrees F (175 degrees C).
Combine ground beef, bread crumbs, egg, garlic, Parmesan cheese, parsley, and Italian seasoning in a large bowl. Mix with your hands until well combined. Shape mixture into 12 meatballs, and place in a baking dish.
Overhead of a ground beef mixture being formed into balls and placed on a baking dish.
Bake meatballs in the preheated oven until cooked through, 15 to 20 minutes. An instant-read thermometer inserted into the center should read at least 160 degrees F (71 degrees C).
While the meatballs are cooking, cut baguette in half lengthwise and open like a book. Remove and discard some of the bread from the inside to make a well for the meatballs.
Brush baguette with olive oil and season with garlic powder and salt. Place baguette on a baking tray, open and with the oiled sides facing up.
Overhead of a baguette cut in half and brushed with olive oil with salt in a bowl off to the side.
When the meatballs have 5 minutes left, slip the baguette into the oven and cook until lightly toasted.
Meanwhile, warm spaghetti sauce in a saucepan over medium heat.
Remove meatballs from the oven. Use a slotted spoon to transfer them to the hot sauce; mix gently to coat with sauce.
Overhead of meatballs cooking in a skillet covered in spagetti sauce.
Overhead of meatballs and cheese resting on a baked baguette.
Return to the oven until cheese is melted, 2 to 3 minutes.
Overhead of meatballs covered in melted cheese resting on a baked baguette.
Cool slightly, then cut into 4 sandwiches