In a large pot or Dutch oven, brown the ground beef over medium heat until fully cooked. Drain any excess fat.
Add the diced onion and minced garlic to the pot and sauté until the onion is translucent, about 3-5 minutes.
Stir in the diced potatoes, beef broth, Worcestershire sauce, and mustard. Bring to a boil, then reduce heat and simmer until the potatoes are tender, about 15 minutes.
Once the potatoes are cooked, add the milk and shredded cheddar cheese. Stir until the cheese is melted and the soup is creamy.
Season with salt and pepper to taste. Add the diced tomatoes and stir to combine.
Let the soup simmer for another 5 minutes, then serve hot.
Garnish each bowl with shredded lettuce, diced pickles, and crumbled bacon if desired.