Cook macaroni in a large pot of salted boiling water until al dente according to package directions. Before draining, reserve ½ cup of the starchy pasta water.

While pasta cooks, heat butter in a large skillet over medium heat. Add minced garlic and sauté for 30 seconds until fragrant. Add chopped onion and bell peppers, cooking for 4-5 minutes until vegetables are softened and onions turn translucent.

Crumble the ground beef into the skillet, breaking it up with a wooden spoon. Cook for 5-7 minutes without stirring initially to get good browning, then break apart and continue cooking until no pink remains. Drain excess fat if needed, then season generously with salt, pepper, paprika, and chili flakes.

Reduce heat to low to prevent cheese from becoming grainy. Stir in room temperature cream cheese, mozzarella, and torn cheese slices. Stir slowly and constantly until everything melts into a smooth, silky sauce.

Add the cooked pasta and reserved pasta water to the skillet. Gently fold everything together for 1-2 minutes until every noodle is coated in the creamy cheese sauce. Add more pasta water gradually if the sauce seems too thick.

Remove from heat and garnish with fresh chopped parsley. Serve immediately while hot and creamy for the best texture and flavor.