01 - Bring a large pot of salted water to a boil. Cook elbow macaroni according to package directions until al dente. Drain through a colander and set aside.
02 - Heat olive oil in a large skillet or Dutch oven over medium heat. Add the chopped onion and sauté for 3 minutes until softened and translucent.
03 - Stir in the minced garlic and diced red bell pepper. Continue sautéing for 2 minutes until fragrant.
04 - Add ground beef to the skillet, breaking it apart with a wooden spoon. Cook until fully browned and no pink remains. Drain any excess fat.
05 - Season the beef with chili powder, ground cumin, smoked paprika, salt, and black pepper. Stir and cook for 1 minute to bloom the spices.
06 - Stir in the tomato paste, canned diced tomatoes, drained kidney beans, and beef broth. Mix thoroughly and bring to a simmer.
07 - Reduce heat to medium-low and let the chili simmer uncovered for 10 minutes, stirring occasionally, until the sauce thickens and flavors meld.
08 - Fold in the cooked macaroni, milk, shredded cheddar cheese, and half of the mozzarella. Stir until the cheeses are fully melted and everything is evenly coated.
09 - Sprinkle the remaining mozzarella over the top. Cover and let rest off heat for 2 to 3 minutes until melted, or place under a broiler for a golden bubbly crust.
10 - Serve hot directly from the skillet, garnished with additional cheese or fresh herbs if desired.