3 hamburger buns, diced into 1-inch cubes
4 slices bacon, diced
1 tablespoon olive oil
8 ounces ground beef
1/4 cup unsalted butter
2 cloves garlic, minced
1 onion, diced
2 stalks celery, diced
2 carrots, grated
1 teaspoon Worcestershire
3 tablespoons all-purpose flour
2 1/2 cups chicken broth
2 cups milk, or more, as needed
2 russet potatoes, peeled and cubed
1 1/2 cups shredded cheddar cheese
Kosher salt and freshly ground black pepper, to taste
2 tablespoons chopped chives
Preheat oven to 400 degrees F. Spread bread cubes in a single layer on a baking sheet. Place into oven and bake until crisp and golden, about 10-15 minutes; set aside.
Heat a large skillet over medium high heat. Add bacon and cook until brown and crispy, about 6-8 minutes. Transfer to a paper towel-lined plate; set aside.
Heat olive oil in a saucepan over medium high heat. Add ground beef and cook until browned, about 3-5 minutes, making sure to crumble the beef as it cooks; drain excess fat and set aside.
Melt butter in a large stockpot or Dutch oven over medium heat. Add garlic, onion, celery, carrots and Worcestershire. Cook, stirring frequently, until onions have become translucent, about 2-3 minutes.
Whisk in flour until lightly browned, about 1 minute. Gradually whisk in chicken broth and milk, and cook, whisking constantly, until slightly thickened, about 1-2 minutes. Stir in potatoes.
Bring to a boil; reduce heat and simmer until potatoes are tender, about 12-15 minutes. Stir in ground beef, cheese, salt and pepper, to taste. If the soup is too thick, add more milk as needed until desired consistency is reached.
Serve immediately, garnished with croutons, bacon and chives, if desired.