Cheeseburger Soup

In a large stock pot cook the ground beef over medium high heat, breaking apart. After it begins to brown add onions, and garlic. Cook until the meat is cooked through, and the onions are soft. Drain any fat from the pan.
Stir in Worcestershire sauce, tomato sauce and chicken stock. Simmer.
In a liquid measuring cup whisk together milk and flour until smooth. Slowly stir into the simmering soup. Cook until the soup starts to thicken slightly.
Add the cheddar cheese, ½ cup at time, stirring after each addition.
Once the cheese is all added stir in the mustard, ketchup, salt and pepper. Cover and simmer for 10 minutes.
Serve with desired garnish.
Store in an airtight container for up to 4 days. Freezes well.

Adapted from The Runaway Spoon