Preheat the oven to 350°F (175°C).

In a large bowl, combine the ground beef, bread crumbs, egg, minced garlic, Parmesan cheese, parsley, and Italian seasoning.

Mix everything together with your hands until well combined.

Shape the mixture into 12 meatballs and place them in a baking dish.

Bake the meatballs in the preheated oven for 15 to 20 minutes, or until they are cooked through.

Use an instant-read thermometer to ensure the meatballs reach an internal temperature of at least 160°F (71°C).

While the meatballs are baking, cut the French baguette in half lengthwise, and open it like a book.

Remove and discard some of the inner bread to create a well for the meatballs.

Brush the cut sides of the baguette with olive oil and season with garlic powder and salt.

Place the baguette on a baking tray, open-side up.

When the meatballs have 5 minutes left to cook, place the baguette in the oven and bake until lightly toasted.

While the bread and meatballs are cooking, heat the spaghetti sauce in a saucepan over medium heat.

Once the meatballs are cooked, remove them from the oven.

Use a slotted spoon to transfer the meatballs into the hot sauce and gently stir to coat them in the sauce.

Spoon the meatballs and sauce into the well of the toasted baguette.

Top with slices of provolone cheese.

Return the baguette to the oven and bake for 2 to 3 minutes, or until the cheese is melted.

Let the sandwich cool slightly before cutting it into 4 portions. Serve and enjoy!