01 - Heat olive oil in a large pot or Dutch oven over medium heat. Add the ground beef and cook until thoroughly browned, breaking it apart with a spoon, about 5 minutes. Drain any excess fat if necessary.
02 - Add the diced onion, minced garlic, and diced bell pepper to the pot. Sauté for 3 to 4 minutes until the vegetables have softened and become fragrant.
03 - Stir in the chili powder, ground cumin, smoked paprika, salt, black pepper, and cayenne pepper. Cook for 1 minute, stirring constantly, until the spices are fragrant and evenly coat the beef mixture.
04 - Add the tomato paste and cook for 1 additional minute. Stir in the diced tomatoes with their juices and the drained kidney beans until well combined.
05 - Pour in the broth and bring the mixture to a gentle simmer, allowing the flavors to begin melding together.
06 - Stir in the uncooked elbow macaroni. Reduce the heat to low, cover the pot, and cook for 10 to 12 minutes, stirring occasionally to prevent sticking, until the pasta is tender and has absorbed the flavors.
07 - Remove from heat and stir in the butter and milk. Add the shredded cheddar cheese and stir vigorously until completely melted and the sauce is smooth and creamy. Adjust seasoning to taste.
08 - Serve hot, garnished with extra shredded cheese or chopped green onions if desired.