1. Step 1: Cook the Beef

2. In a large pot over medium heat, cook the ground beef until browned and crumbly. Drain any excess fat from the pot.

3. Step 2: Add the Vegetables

4. Stir the sliced mushrooms, diced onion, and minced garlic into the pot with the browned beef. Cook until the mushrooms are tender and the onions are translucent.

5. Step 3: Add the Liquids and Seasonings

6. Pour in the fire-roasted diced tomatoes and the beef broth. Stir in the steak seasoning, salt, garlic powder, and black pepper. Allow the soup to simmer for 15-20 minutes, letting the flavors meld together.

7. Step 4: Prepare the Buns

8. While the soup is simmering, toast the mini burger buns and spread them with a generous amount of mayonnaise.

9. Step 5: Serve and Enjoy

10. Ladle the hot Bacon Mushroom Swiss Cheeseburger Soup into bowls, then top each serving with chopped cooked bacon and shredded Swiss cheese. Serve the toasted, mayonnaise-spread buns alongside the soup for the complete cheeseburger experience in a bowl.