Bring a large pot of water to a boil. Cook egg noodles according to package directions.
Meanwhile, place the ground beef and Italian sausage in a large skillet. Cook, breaking the meat up, until the meat is browned and cooked through. Stir in half of the oregano and garlic salt.
Preheat oven to 350°F. Spray a 13x9 inch pan with cooking spray. Place half of the cooked noodles in the bottom, followed by half of the meat and half of the sauce. Repeat with the remaining noodles, meat, and sauce. Top with the cheese and sprinkle with the remaining oregano.
Bake for 20 minutes, or until the casserole is warm throughout and the cheese has melted.
To make ahead: follow the recipe as written, but do not bake the casserole. Refrigerate the casserole until you're ready to bake it. The casserole can be refrigerated for up to one day before baking. You can use 80% lean, 85% lean, or 90% lean ground beef for this casserole (I used 85%).