Heat a large skillet over medium-high heat and brown the ground beef, breaking it into small crumbles as it cooks, about 8-10 minutes. While the beef cooks, dice the onion into 1/4-inch pieces, seed and dice the red bell pepper, and mince the garlic. Once the beef is fully browned with no pink remaining, transfer it to your crockpot using a slotted spoon to leave excess fat behind.

Add the diced onion, bell pepper, and minced garlic to the browned beef in the crockpot. Pour in the crushed tomatoes and beef broth, then add the salt, black pepper, Italian seasoning, and smoked paprika. Stir everything together until the spices are evenly distributed and the beef is coated with the liquid. The flavor foundation is now set for a long, slow braise.

Cover the crockpot and cook on low for 6-8 hours (or on high for 3-4 hours if you're short on time). This extended cooking time allows the flavors to deepen and meld together beautifully. I find that low heat creates the most tender, flavorful results, even though high heat will get you there faster if needed.

About 15 minutes before you're ready to serve, pour the milk into the crockpot and stir in the uncooked macaroni, making sure the pasta is submerged in the liquid. Increase the heat to high, cover, and cook for 15-20 minutes, stirring occasionally to prevent sticking. The pasta will absorb the flavorful broth and become tender while the sauce becomes creamy.

Turn off the heat and add the shredded cheddar cheese in batches, stirring after each addition until completely melted and incorporated. I recommend shredding cheese from a block rather than using pre-shredded, as it melts much more smoothly without the anti-caking agents. Let the dish rest for 2-3 minutes to allow the cheese to fully incorporate into the creamy sauce, then serve directly from the crockpot.