1. Preheat oven to 350F.
2. Bring a large pot of lightly salted water to a boil and cook spaghetti until ‘al dente’.
3. Place the chunks of butter in the drained spaghetti and mix until coated, then set aside.
4. In a large skillet over medium-high heat, add the diced onions, pepper, garlic and olive oil. Cook until onions are slightly tender. Then add the ground beef and cook until browned. Drain any excess grease.
5. Add the jar of pasta sauce and fresh parsley to the skillet, mixing well. Reduce to low heat to simmer.
6. In a large mixing bowl, combine cream cheese, sour cream, and cottage cheese until well blended.
7. Add the cooked spaghetti to the large bowl with the creamy mixture and toss until well coated.
8. In a 9×13-inch casserole dish, pour the creamy spaghetti mixture and top with 3/4 of the pasta sauce. Toss well.
9. Add half of the shredded Cheddar and half of the Mozzarella cheese to the creamy spaghetti mixture and toss again.
10. Pour the remaining pasta sauce evenly over the top of the spaghetti.
11. Top with the remaining cheeses evenly.
12. Bake in the preheated oven for about 25 minutes or until the cheese is fully melted.
13. Enjoy!