01 - Heat a large deep skillet or sauté pan over medium-high heat. Add ground beef and cook, breaking it apart with a spoon, until browned and no longer pink, approximately 5 minutes. Drain excess fat if necessary.
02 - Add diced onion, garlic, and bell pepper to the beef. Sauté until softened, about 3 to 4 minutes.
03 - Stir in chili powder, cumin, smoked paprika, oregano, salt, black pepper, and cayenne if using. Cook for 1 minute until fragrant.
04 - Add tomato paste, diced tomatoes with juices, kidney beans, beef broth, and uncooked macaroni. Stir thoroughly to combine and bring to a simmer.
05 - Reduce heat to medium-low, cover, and cook for 12 to 15 minutes, stirring occasionally, until pasta is tender and most liquid is absorbed.
06 - Stir in milk and 1½ cups cheddar cheese until melted and creamy throughout.
07 - Sprinkle remaining ½ cup cheddar cheese over the top. Cover the skillet for 2 to 3 minutes to allow the cheese to melt completely.
08 - Remove from heat and garnish with fresh cilantro or green onions if desired. Serve immediately while hot.