Heat a large skillet over medium-high heat and cook the ground beef with the onion, garlic, and seasonings until fully browned. Drain excess grease, if needed, before continuing.
Add the tomato paste and Worcestershire sauce and stir until fully combined.
Pour in the beef broth, add the elbow macaroni, stir, and bring to a simmer. Cover and cook for 10 minutes, stirring every 2–3 minutes to prevent the pasta from sticking or clumping.
Uncover and stir in the milk, sour cream, and 1 cup of the shredded cheese (keep the rest for topping). Use room-temperature dairy for smooth blending. The casserole should be thick and creamy. If it looks too watery, continue to simmer uncovered for 1–2 more minutes.
Top with the remaining cheese, cover, and heat for 2-3 minutes or until the cheese is melted. Scoop into bowls and serve warm — it’s pure comfort in one pan.
Just before serving, garnish with chopped fresh parsley or green onion for a pop of color and freshness.