In a large skillet over medium heat add diced onion and oil and saute until softened.
Add garlic and cook, stirring, for an additional minute.
Remove to a plate and add ground beef to the skillet.
Cook, crumbling, over medium heat until browned. Drain if needed.
Add cooked beef, onions, and 6 slices of chopped bacon to a large Crock-pot.
Add in all the seasonings along with mustard and Worcestershire.
Next, add drained and rinsed black, pinto, and kidney beans to the Crock-pot.
Finally, add beef broth, both cans crushed tomatoes, and tomato sauce. Stir to combine.
Cover and cook for 7-8 hours on low.
Remove lid and add remaining 2 slices chopped bacon and 1 cup shredded cheddar cheese.
Scoop into bowls and serve warm.