Put 1 cup of the flour in a shallow bowl and season with salt and pepper. Dredge the beef in the seasoned flour and set aside.
Heat a heavy skillet on medium-high heat, add the bacon and cook until crisp. Set the bacon aside, leaving the drippings behind in the skillet (chop the bacon and reserve for serving). In batches, brown the beef in the skillet, adding olive oil if necessary, about 3 minutes per batch. Transfer each batch to the slow cooker as it browns.
Add the butter and remaining 3 tablespoons flour to the skillet. Cook 3 minutes, stirring with a whisk. Whisk in the tomato paste. Turn off the heat, pour in the beef broth and whisk to get all the ingredients incorporated with the brown bits from the bottom of the skillet. Add the mixture to the slow cooker.
Add the beets, carrots, potatoes, Brussels sprouts, red wine, parsley, Worcestershire, allspice, garlic, bay leaves and onions. Set the cooker to low and cook for 8 hours.
Serve in bowls sprinkled with the reserved bacon.