1. Bring a large pot of salted water to a boil. Cook spaghetti until al dente. Reserve 1 cup of pasta water, then drain and set aside.

2. In a large skillet, heat olive oil or butter over medium heat. Add diced onion and sauté for 3–4 minutes until soft. Add minced garlic and cook for 30 seconds.

3. Add ground beef and break it up with a spoon. Cook for 6–8 minutes, until browned. Stir in Cajun seasoning and let it cook for another 2 minutes.

4. Reduce heat and pour in the heavy cream. Add cream cheese and stir until melted and smooth.

5. Gradually stir in mozzarella and Parmesan cheese, mixing well to create a creamy sauce. Add pasta water a little at a time if the sauce is too thick.

6. Toss the cooked spaghetti into the sauce and beef mixture. Stir gently to coat every strand.

7. Taste and adjust seasoning with salt and black pepper if needed. Serve hot, garnished with extra Parmesan or parsley if desired.