Starting out, sear meatballs on both sides then add marinara.
Cover and let cook until meatballs are cooked completely.
Melt butter and add parm garlic seasoning, stir up then brush onto the sides of bread you want to toast.
Toast bread until it reaches your desired color.
Assemble sandwich, meatballs in bottom, cheese. You can even put it under the broiler to melt the cheese if you would like. Serve hot!