Preheat the oven to 350 degrees F (175 degrees C).
In a medium bowl, gently mix by hand the ground beef, bread crumbs, Italian seasoning, garlic, parsley, Parmesan cheese, and egg. Shape into 12 meatballs, and place in a baking dish.
Bake for 15 to 20 minutes in the preheated oven, or until cooked through. Meanwhile, cut the baguette in half lengthwise, and remove some of the bread from the inside to make a well for the meatballs. Brush with olive oil, and season with garlic powder and salt. Slip the baguette into the oven during the last 5 minutes of the meatball's time, or until lightly toasted.
While the bread toasts, warm the spaghetti sauce in a saucepan over medium heat. When the meatballs are done, use a slotted spoon to transfer them to the sauce. Spoon onto the baguette and top with slices of provolone cheese. Return to the oven for 2 to 3 minutes to melt the cheese. Cool slightly, cut into servings, and enjoy!