Bangers & Mash with Red Onion Gravy. Enough gravy and Mash for 4 people, Sausages of your choice! Gravy. 2 red onions Pinch of salt 2 tbsp balsamic 1 tbsp soy sauce 3 tbsp Worcestershire Sauce 500ml chicken stock 500ml beef stock Mash. 800g Maris piper potatoes 100g butter 100ml milk Salt to taste Handful of chopped chives 1. to make the gravy add the lardons to a pan and render out the fat, add the onions with a pinch of salt and the thyme. Once caramelised add the Worcestershire sauce and cide