Trim the brussel sprouts, removing any damaged outer leaves. Shred the brussel sprouts by by cutting them into very thin slices using a knife or mandolin.
In an oven proof skillet cook the bacon until crisp and then roughly chop into small pieces and set aside. Reserve approx 1 tbsp of the bacon grease in the skillet and add in the onion and cook it for 8-10 minutes until soft and golden in colour.
Add the shredded brussel sprouts to the skillet and stir well. Add in the veg or chicken stock, mustard, apple cider vinegar and black pepper and leave to cook for approximately 6 minutes until the brussel sprouts are tender and slightly golden in colour. Stir in the chopped bacon.
Create 4 wells in the mixture using a spoon. Crack an egg into each of the wells. To cook the eggs you can cover the pan with a lid and cook on medium low heat for 5-7 minutes. Alternatively you can transfer the skillet to the oven and bake at 175 degrees C (350F) for 8 minutes or until the eggs are cooked to your liking. Sprinkle with fresh chopped parsley or chilli flakes before serving.