In a large, deep skillet,on medium heat, cook bacon until crisp. Remove to paper towels to drain. Pour off all but about 2 to 3 tablespoons of fat and saute onion and celery til onion is somewhat translucent. Add chicken stock, red pepper flakes and cabbage. Cover and simmer til cabbage is tender/crisp. season to taste with salt and pepper. Crumble bacon and