In a Dutch oven or medium heavy bottomed pot over medium heat, add bacon halves and cook until crispy, about 7 minutes. Transfer bacon to a paper towel-lined plate. Leave fat in pot.
Add the ground beef, breaking it up with a wooden spoon and season with salt and pepper. Cook beef until browned, stirring occasionally. Drain half the fat and transfer beef to another paper towel lined plate.
Melt the butter in the pot then add the onion and celery and sauté for 4-5 minutes.
Stir in the garlic and cook for 30 seconds, until fragrant. Add flour and stir to coat vegetables and cook for about 2 minutes. Slowly whisk in chicken broth until flour dissolves and there are no lumps.
Stir in the cream, potatoes, and add the beef back to the pot. Increase the heat to medium-high and bring the soup to a boil, then reduce heat to a simmer. Allow to simmer for about 15 minutes, with cover ajar, until the potatoes are tender and the soup has thickened.
Meanwhile, slice bun and slather in butter on each half. Toast in the oven and then cut into cubes.
Remove pot from heat and stir in cheeses. Add half the bacon and stir. Add soup to bowls and garnish with extra cheese, bacon, pickle bits and bun croutons.