Heat a large pot over medium-high heat and add the ground beef, breaking it into small pieces as it cooks. Once the beef is mostly browned (about 5-7 minutes), add the diced onion and continue cooking for another 2-3 minutes until the onion softens slightly. The beef should be fully cooked and lightly caramelized at the edges. Drain off excess fat if needed, leaving just enough to coat the bottom of the pot—this helps carry flavor in the next step.

With the heat still on medium-high, stir in the tomato paste and cook it directly in the pot for about 1 minute, stirring constantly. This caramelizes the tomato paste slightly and deepens its flavor. Then add the garlic powder, chili powder, and dry mustard powder, stirring to coat everything evenly. I like to add these spices to the tomato paste first rather than to liquid—it concentrates their flavor and prevents them from clumping. Cook for another 30 seconds just to toast the spices slightly.

Pour in the beef broth and stir well to combine all the seasoned elements from the bottom of the pot. Bring the mixture to a boil over medium-high heat, then add the macaroni and stir to prevent sticking. The broth should come to a rolling boil once the pasta is added. Reduce the heat to medium and let it simmer uncovered for 13-15 minutes, stirring occasionally, until the pasta is tender and most of the broth has been absorbed.

Remove the pot from heat and immediately stir in the freshly shredded cheddar cheese until it's completely melted and incorporated throughout—the residual heat will melt it smoothly without any graininess. Taste the dish and add salt and pepper to your preference, keeping in mind that the broth and cheese already contain some salt. Stir everything together one final time and serve hot. I find that freshly shredded cheese melts much better than pre-shredded, giving the dish a creamier texture.