Bring a large pot of salted water to a boil and cook the macaroni until just tender, about 8 to 10 minutes. Save about 125ml of the pasta water then drain the pasta.
Heat 1 to 2 tablespoons of butter in a large skillet over medium heat. Add the minced garlic, chopped onion, and bell peppers and cook for 4 to 5 minutes until soft and translucent.
Add the ground beef to the skillet, breaking it apart as you cook. Let it brown evenly for 5 to 7 minutes then drain any extra fat. Season the mixture with salt, pepper, paprika, and chili flakes.
Turn the heat down to low and mix in the cream cheese, shredded mozzarella, and cheese slices. Stir continuously until the cheeses are completely melted and creamy, about 3 to 4 minutes.
Combine the cooked macaroni with the cheesy beef mixture, adding reserved pasta water gradually until the sauce reaches your preferred consistency. Stir well to coat everything.
Garnish with fresh parsley if desired and adjust seasoning before serving for the best flavor.