In a medium skillet, brown ground beef until no pink remains. Crumble into smaller bits. Drain and set aside.
In a large Dutch oven or pot, melt unsalted butter. Add chopped onion and potato. Saute until onion starts to soften and potatoes brown, approximately 3-4 minutes.
Add flour, tossing to coat.
Pour in chicken broth and milk. Add fine sea salt, ground black pepper and garlic powder. Stir and bring to a low simmer.
Simmer until potatoes are soft, approximately 10 minutes.
Stir in shredded cheese and sour cream. Continue to stir until incorporated.
Before serving, add tomatoes and cooked ground beef.
Top each bowl with shredded lettuce, crumbled bacon and Hot Dog Bun Croutons.
Even though this Bacon Cheeseburger Soup isn't a slow cooker recipe, you can transfer the finish product into a slow cooker and keep on low to serve at parties. Set bowls with the garnishes out so people can make their own soup just like a burger bar! In a pinch, you can use condensed canned Cheddar Soup instead of making the soup base from scratch. Follow the can instructions for adding water and omit cheddar cheese, chicken stock and milk.