Boil spaghetti in salted water until al dente. Drain and set aside.
In a large pan over medium heat, brown the ground beef and Italian sausage with diced onion and minced garlic. Drain any excess fat.
Stir the spaghetti sauce into the meat mixture and simmer 3–5 minutes.
In a bowl, combine cream cheese, sour cream, cottage cheese, ricotta, parmesan, and pepper. Mix until smooth.
Grease a 9x13-inch dish with butter or cooking spray. Spread half the pasta on the bottom, then half the meat mixture, and half the cheese mixture. Repeat layers with the remaining pasta, meat, and cheese.
Preheat oven to 350°F and bake 25–30 minutes until bubbly and lightly golden.
Let the casserole rest 5 minutes before slicing and serving.