London Pie and Mash Liquor

Liquor is not gravy and it is not brown. It is the pale green parsley sauce that comes over a pie and mash in the old East End shops, and it is one of the last proper working class London dishes still being served. Traditionally it was made with the water from stewing eels, which is why it has that faint savoury saltiness. This version uses fish stock so you can get close at home, with a vegetarian route in the variations.

Ingredients

Makes about 700ml, enough for six plates

• 40g (1½oz) butter
• 40g (1½oz) plain flour
• 800ml (1½ pints) fish stock or the water from stewing eels if you are doing it properly
• 1 large bunch (about 60g / 2oz) flat leaf parsley stalks and all, chopped very fine
• 2 tsp malt vinegar plus more on the table
• ½ tsp ground white pepper
• salt

Kit

• Saucepan
• Whisk
• Sharp knife for the parsley

Method

1. Chop the parsley as finely as you can, stalks included. The stalks carry most of the colour and flavour and throwing them away is the main reason home made liquor comes out pale and weak.

2. Melt the butter in a saucepan over a medium low heat and stir in the flour. Cook for 2 minutes, stirring constantly, keeping it blond. Any colour on the roux and the finished liquor goes beige instead of green.

3. Add the fish stock a third at a time, whisking hard until each addition is completely smooth before the next. Bring to a gentle simmer.

4. Simmer for 6 to 8 minutes, whisking now and then, until it thickens to something like single cream. Liquor is thin. It should flood the plate and run between the mash and the pie, not sit on top like custard.

5. Add about two thirds of the parsley and simmer for 2 minutes only. Cooking parsley for longer than that turns it from bright green to a dull olive.

6. Take the pan off the heat, stir in the rest of the parsley raw, and it will go a proper fresh green. That two stage approach is what gets both the flavour and the colour.

7. Add the vinegar and white pepper, then season with salt. Taste it: it should be sharp, herby and a bit salty, and it should not taste like a béchamel. Serve straight away with more vinegar on the table.

Tips worth knowing

• Do not use dried parsley or a food processor. Dried parsley gives you no colour at all, and a processor bruises it into a dull green paste rather than clean flecks.
• The right consistency is thinner than most people expect. If it holds a peak, it is wrong. Loosen it with more stock until it pours freely.
• White pepper and malt vinegar are the two flavours that make it taste like a pie shop. Black pepper and wine vinegar taste noticeably different.
• Make it just before serving. Liquor sitting in a pan for half an hour goes grey green and thickens, and neither is fixable.

Keeping and reheating

Best eaten immediately. It will keep a day in the fridge but the colour dulls badly and it thickens into a paste. If you must reheat it, do it gently with extra stock and stir a fresh handful of raw parsley through at the end.

Questions people ask