Cook bacon in a large pot or Dutch oven until crispy. Remove bacon from pot and set aside.
Leave about 2-3 tablespoons of bacon grease in the pot. You can save any excess bacon grease for another use.
Cook the onion in the bacon grease until soft.
Add cabbage, chicken broth, and red pepper flakes. Cover pot and simmer for about 10 minutes, opening it to stir once or twice.
Remove lid from pot and cook uncovered for about 15 minutes. Turn up the heat a little so you get a good amount of evaporation.
Season to taste with pepper. If desired, add a little salt.
Crumble the bacon and mix it into the cabbage mixture. Serve in small bowls with with the broth.