Cut the baguette into 4 equal sections, then slice each section in half lengthwise, but not all the way through (they should open like a book). If desired, scoop out some of the bread from the center to make more room for the filling.
Garlic Butter (Optional):
In a small bowl, mix the olive oil with minced garlic. Brush the inside of each baguette section with the garlic oil for extra flavor. This step is optional but adds a nice touch.
Add the Meatballs and Sauce:
Place 3-4 meatballs in each baguette section, depending on the size of your baguette and meatballs. Spoon marinara sauce over the meatballs, making sure each one is well-coated.
Add the Cheese:
Sprinkle shredded mozzarella and grated Parmesan cheese over the meatballs and sauce. Season with a little salt and pepper to taste.
Bake:
Arrange the filled baguette sections on a baking sheet. Bake in the preheated oven for 10-15 minutes, or until the cheese is melted and bubbly, and the bread is toasty.
Garnish and Serve:
Remove the meatball boats from the oven and let them cool for a couple of minutes. Garnish with fresh basil leaves if desired. Serve with extra marinara sauce on the side for dipping.