Cook the spaghetti according to package directions in salted boiling water until al dente. Drain and set aside.
In a large skillet over medium heat, cook the chopped bacon until crispy. Remove half the bacon and set aside; leave rendered fat in the pan.
Add ground beef to the same skillet and cook until browned and no longer pink, breaking it up with a spoon. Drain excess grease if needed.
Add onion and garlic to the skillet and sauté until softened, about 5 minutes.
Stir in crushed tomatoes, tomato paste, oregano, basil, red pepper flakes, salt, and black pepper. Simmer for 15 minutes.
Reduce heat to low and stir in heavy cream and milk. Simmer gently for 10 minutes.
Preheat oven to 375°F (190°C). In a large baking dish, combine cooked spaghetti with the tomato-cream sauce. Top evenly with mozzarella and Parmesan cheeses.
Bake uncovered for 20–25 minutes, or until bubbly and cheese is golden and slightly browned.
Garnish with reserved crispy bacon and fresh parsley before serving.
Notes
Serve hot and enjoy this decadent twist on classic spaghetti!