The encyclopaedia of gravy
Sausages and mash demand onion gravy: sweet, dark, generous and thick enough to sit in the well of the mashed potato.
This is the most settled question on Gravypedia. Bangers and mash wants onion gravy, made properly, with onions cooked for 25 to 30 minutes until they collapse into sweetness.
Why onion gravy specifically¶
Sausages are salty, fatty and coarse. Mash is bland and absorbent. The gravy has to do two jobs: provide sweetness against the salt, and provide enough body to sit in the crater of the mash rather than run off the plate. Caramelised onions deliver both — sugar from the onions, texture from the strands.
Consistency¶
Make it thicker than a roast gravy. A roast gravy should flood the plate; a bangers-and-mash gravy should pool. Aim for 40 g fat and 40 g flour per 500 ml instead of 30 g.
The method in short¶
- Slice 2 large onions thinly and cook in 25 g butter with a little oil over medium-low heat for 25–30 minutes, until deeply caramelised.
- Stir in 1 tbsp flour, cook 2 minutes.
- Add 500 ml beef stock gradually, or 350 ml stock plus 150 ml stout, reduced.
- Simmer 10 minutes. Finish with a dash of Worcestershire sauce or balsamic.
Full version: onion gravy.
Fry the sausages first, in the same pan¶
The best version uses the sausage pan. Fry the sausages, lift them out, cook the onions in the fat they left, and build the gravy on top. The browned residue from the sausages goes straight into the gravy — see deglazing a roasting tin for the technique, which works identically in a frying pan.
💡 Chef's tip
A teaspoon of English mustard stirred in at the end is traditional in pubs across the north of England and makes a real difference.
Vegetarian and vegan¶
Onion gravy is the easiest gravy to make meat-free convincingly, because the onions are doing the work. See vegan gravy.