Bring a large pot of water to a boil over high heat. Add the kosher salt and pasta. Cook according to the package directions until just al dente, usually 9–11 minutes. Before draining, reserve ½ cup (120 mL) of the pasta cooking water. Drain the pasta and set aside.

While the pasta cooks, heat the olive oil in a large 12-inch skillet over medium-high heat. Add the ground beef and cook for 6–8 minutes, breaking it into small crumbles. The beef should be fully browned with no pink remaining and should reach an internal temperature of 160°F (71°C) . Drain excess grease if needed.

Reduce the heat to medium: Add the diced onion to the skillet and cook for 3–4 minutes, until softened. Stir in the minced garlic and cook for another 30 seconds, until fragrant.

Add the chili powder, cumin, smoked paprika, oregano, kosher salt, and black pepper. Stir for about 30 seconds so the spices coat the beef and become fragrant. Add the tomato paste and cook for another minute. The mixture should look evenly seasoned and slightly darker.

Pour in the diced tomatoes with their juices and the beef broth. Stir well, scraping up any browned bits from the bottom of the skillet. Bring the mixture to a gentle simmer and cook for 4–5 minutes, until it thickens slightly.

Reduce the heat to medium-low: Add the softened cream cheese in small pieces. Stir until it melts completely into the sauce. The sauce should become creamy and smooth. If you see small cream cheese lumps, continue stirring over low heat until they disappear.

Add the shredded cheddar a handful at a time, stirring after each addition. Continue until the cheese is fully melted and the sauce looks thick and glossy. Avoid letting the sauce boil vigorously after adding the cheese, which can make it grainy.

Add the drained pasta to the skillet: Fold gently until every piece is coated in the beef and cheese sauce. If the sauce seems too thick, add the reserved pasta water 2 tablespoons at a time until it reaches a creamy, spoonable consistency.

Cook over low heat for 2–3 minutes, stirring occasionally. The pasta should be hot throughout and evenly coated, with no watery liquid collecting at the bottom of the skillet. Taste and adjust the seasoning if needed.

Remove the skillet from the heat and let the pasta rest for 5 minutes. The sauce will thicken slightly as it sits. Top with the optional cilantro, scallions, or sour cream just before serving.