A classic dish in Great Britain, bangers and mash is made with bratwurst and sausages, mashed potatoes, and a rich onion gravy. Traditionally made with beer but can also be made without it.
In a large skillet, brown bratwurst on two sides, if fully cooked, or cook them according to package directions if uncooked. If browning, this should take about 3-4 minutes per side.
Remove bratwurst from pan, set aside, and keep warm.
Using same pan, add 2 Tbsp olive oil and sliced onions and cook over medium heat. Stir frequently until onions have softened and begun to caramelize, about 5-6 minutes.
Add beef stock and beer if using. Allow the liquids to cook at a high simmer for about 10 minutes. This will allow the liquids to reduce.
In a small bowl, combine cold water and flour to make a thin paste. Stirring the whole time, slowly add the flour mixture to the onion and stock in the pan.
Cook until the gravy begins to thicken, about 3-4 minutes. Add mustard, Worcestershire sauce, sugar (if using beer), salt and pepper.
Serve over prepared mash potatoes and bratwurst.
Notes
We like to serve this with soda bread and honey carrots or green beans.