Philly Cheesesteak Meatballs

Name: Philly Cheesesteak Meatballs
Prep time: 15 min
Cook time: 15 min
Total time: 30 min
Cuisine: American
Ingredients: 1 Tablespoon olive oil; 1/4 cup onion (fine diced); 18 1/2 inch cubes provolone cheese (about 2 ounces); 1/3 cup panko breadcrumbs (Gluten Free for GF Version); 1/4 cup parmesan cheese (grated); 1/4 cup fresh parsley (chopped); 1 large egg; 1 clove garlic (minced); 1/2 teaspoon Garlic & Herb Seasoning (recipe on blog); 1/2 teaspoon salt; 1/2 teaspoon pepper; 1 pound ground beef; 1 Tablespoon butter; 1 Tablespoon flour (or arrow root for gluten free); 1 cup milk; 6 ounces provolone cheese (grated); 1/2 cup parmesan cheese (grated); salt & pepper to taste; 4 hoagie rolls (or party toothpicks); 1 medium onion (sliced); 8 ounces mushrooms (sliced); 3 Italian long hot peppers or 1 green bell pepper (sliced); 1 Tablespoon olive oil (for sauteeing vegetables)