01 - Bring a large pot of salted water to a boil. Cook elbow macaroni according to package directions until al dente. Drain in 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. Sauté for an additional 2 minutes until fragrant and the pepper begins to soften.
04 - Add the ground beef to the skillet, breaking it apart with a wooden spoon. Cook until fully browned and no pink remains throughout, about 5 to 7 minutes. Drain any excess fat.
05 - Stir in the chili powder, ground cumin, smoked paprika, salt, and black pepper. Cook for 1 minute, stirring constantly, until the spices are fragrant and well distributed.
06 - Add the tomato paste, canned diced tomatoes, drained kidney beans, and beef broth. Stir thoroughly to combine and bring the mixture 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 the flavors meld together.
08 - Stir the cooked macaroni, milk, shredded cheddar cheese, and half of the mozzarella into the chili. Mix gently until the cheeses are fully melted and evenly coated throughout.
09 - Sprinkle the remaining mozzarella over the top. Cover the skillet and let sit off the heat for 2 to 3 minutes until the cheese melts, or place under a broiler for 1 to 2 minutes for a golden, bubbly crust.
10 - Serve hot in bowls, garnished with extra shredded cheese or fresh herbs such as cilantro or parsley if desired.