Brown the Beef
In a large pot, melt 1 tbsp butter over medium heat. Brown the beef, breaking it up as it cooks. Drain excess fat, set beef aside.
Sauté the Veggies
Add remaining butter to the pot. Toss in diced onion, sauté 3–4 mins. Add garlic and cook 1 more minute.
Flavor Base
Stir in tomato paste, Worcestershire, and mustard powder. Cook 1 min. Sprinkle flour over and stir to form a quick roux.
Add Broth & Milk
Slowly pour in broth, whisking to avoid lumps. Add milk. Stir and bring to a gentle simmer.
Add Pasta
Add dry macaroni. Cook 8–10 mins, stirring now and then, until pasta’s tender but not mushy.
Cheese It Up
Reduce heat. Add cheddar and mozzarella. Stir until melted and smooth. Season with salt and pepper to taste.
Bring it All Together
Return browned beef to the pot. Stir and simmer 2–3 minutes until everything’s warm and cozy.
Serve & Garnish
Ladle into bowls. Top with diced pickles, green onions, bacon bits—or whatever burger topping your soul needs.