Keto Chili

In a large pot over medium heat, cook bacon. When bacon is crisp, remove from pot with a slotted spoon. Add onion, celery, pepper, and mushrooms to pot and cook until soft, 6 minutes. Add garlic and cook until fragrant, 1 minute more. Push vegetables to one side of the pan and add beef. Cook, stirring occasionally, until no pink remains. Drain fat and return to heat.  Add chili powder, cumin, oregano, and paprika and season with salt and pepper. Stir to combine and cook 2 minutes more. Add broth and bring to a simmer. Let cook 10 to 15 more minutes, until most of the broth has evaporated.  Ladle into bowls and top with sour cream, reserved bacon, cheese, green onions, and avocado.