Shred the cheddar and Monterey Jack cheese and set aside together. Mince the garlic cloves and have all remaining ingredients measured and ready before you start cooking. This ensures you can build the soup smoothly without interruption once the cooking begins.

Heat the butter in a large pot over medium-high heat. Add the ground beef and cook until fully browned, breaking it apart as it cooks, about 5-7 minutes. Drain excess fat from the pot, leaving just enough to coat the bottom. Add the minced garlic and cook for 1 minute until fragrant. This combination of butter and browned beef creates a flavorful foundation for the soup.

Stir in the taco seasoning, chili powder, Worcestershire sauce, and tomato paste into the cooked beef mixture. Cook for 1-2 minutes, stirring constantly to combine everything and toast the spices slightly. This technique deepens the flavors and prevents the tomato paste from tasting raw. I like to let this mixture cook together briefly so the spices really marry with the beef before adding the liquids.

Pour in the beef broth, chicken broth, milk, and Rotel tomatoes (including their juice). Bring the mixture to a gentle boil over medium-high heat. Once boiling, add the pasta and stir well to submerge it completely. Lower the heat to medium-low so the soup simmers gently rather than rolling aggressively, which prevents the pasta from breaking apart. Cover the pot and cook for the time specified on your pasta box, stirring occasionally to prevent sticking.

Once the pasta is tender (check a few pieces to ensure it's cooked through), turn the heat to low. Remove from heat and stir in the shredded cheddar and Monterey Jack cheese, followed by the Velveeta in small chunks. Stir constantly until all cheese is completely melted and incorporated, which typically takes 2-3 minutes. The Velveeta acts as an emulsifier, helping create a smooth, creamy sauce. Ladle into bowls and serve immediately—I find this soup is best enjoyed right away while it's hot and the cheese is perfectly smooth.