Onion Gravy for Liver and Bacon

Liver and bacon without onion gravy is just liver and bacon, and the gravy is doing more work than either. It has to be savoury enough to stand up to the liver, sharp enough to cut its iron, and it has to be built in the same pan or you throw away the best part. This one takes about twenty five minutes while the liver rests.

Ingredients

Makes about 450ml, enough for four plates

• 6 rashers streaky bacon cooked first, the fat is the base
• 3 medium (about 450g / 1lb) brown onions sliced 5mm thick
• 1 tbsp butter only if the pan looks dry
• 2 tbsp (30g) plain flour some from dusting the liver
• 2 tbsp sherry vinegar
• 550ml (1 pint) hot beef or chicken stock
• 1 tsp Worcestershire sauce
• 1 bay leaf
• salt and black pepper

Kit

• Large frying pan
• Whisk
• Plate for resting

Method

1. Fry the bacon until crisp, lift it out, then dust your liver in seasoned flour and fry it fast, about 90 seconds a side for slices of lamb's liver. Take it out while it is still pink in the middle and rest it on a warm plate. It will finish cooking there.

2. There should now be bacon fat and browned flour in the pan. Add the onions with a pinch of salt and the butter if it looks dry, and cook over a medium heat for 20 minutes, stirring often and scraping up all the stuck flour and meat. That flour is doing part of the thickening already.

3. The base will darken quickly because of the flour from the liver. Whenever it looks like it might catch, add a splash of water and scrape. Do this two or three times over the twenty minutes.

4. Sprinkle in the flour and cook for 2 minutes, stirring so it picks up the bacon fat.

5. Pour in the sherry vinegar and let it bubble away for 30 seconds while you scrape the base clean. The sharpness here is deliberate, because liver has a strong iron flavour and needs acid alongside it.

6. Add the hot stock in two goes, whisking smooth each time, then the Worcestershire sauce and the bay leaf. Simmer for 10 minutes until thick and glossy.

7. Remove the bay, season, then slide the liver and any juices from the resting plate back into the gravy for 1 minute to warm through. Crumble the bacon over the top at the table.

Tips worth knowing

• Do not put raw liver into the gravy to cook. It goes grey and grainy. Fry it separately, rest it, and return it for a minute at the very end.
• The juices that pool under resting liver are worth more than the vinegar. Tip every drop into the gravy.
• Lamb's liver is milder and more forgiving than ox liver. If you are using ox liver, soak it in milk for an hour first and add an extra splash of vinegar to the gravy.
• Thicker onion slices are right here because they need to hold up against the liver, and thin ones vanish.

Keeping and reheating

The gravy alone keeps 3 days in the fridge and freezes for 3 months. Do not store liver in the gravy, as it turns tough and grainy on reheating. Reheat the gravy and add freshly cooked liver.

Questions people ask