Slow Cooker Pot Roast Gravy

A slow cooker gives you meltingly soft beef and about a litre of thin, greasy liquid that most people either pour over the meat as it is or throw away. Neither is right. Twenty minutes on the hob turns that liquid into a dark, glossy gravy that tastes of the whole day's cooking, and cornflour is the right thickener here because there is no fat left to make a roux with.

Ingredients

Makes about 700ml, enough for eight servings

• 1 litre (1¾ pints) cooking liquid from the slow cooker everything left after the beef and vegetables come out
• 2 tbsp cornflour slaked in 4 tbsp cold water
• 1 tbsp Worcestershire sauce
• 1 tsp dark soy sauce for colour
• 1 tsp balsamic vinegar cuts through the richness after eight hours of cooking
• 1 tsp tomato purée optional, for body
• salt and black pepper to taste

Kit

• Fat separator or tall jug
• Wide saucepan
• Sieve
• Small bowl
• Balloon whisk

Method

1. Lift the beef and the vegetables out of the slow cooker and keep them covered and warm. Pour every drop of the remaining liquid through a sieve into a tall jug or a fat separator.

2. Let it stand for ten minutes. A thick layer of fat will rise to the top and it will be much more than you expect. Skim it off with a spoon or pour the liquid out from underneath with a separator. Do not skip this, because unskimmed slow cooker liquid makes an unpleasantly greasy gravy.

3. Pour the defatted liquid into a wide saucepan. Wide matters, because you are about to reduce it and surface area is what makes that happen quickly.

4. Bring it to a proper rolling boil and let it reduce by about a quarter, which takes twelve to fifteen minutes. Taste it as it goes. It will get darker, glossier and considerably more savoury.

5. Stir in the Worcestershire sauce, soy sauce, balsamic vinegar and tomato purée if using. The vinegar sounds odd but eight hours of braising flattens everything, and a little acid brings it all back into focus.

6. Turn the heat down to a simmer. Give the cornflour slurry a stir, because it settles within seconds, then pour it into the pan in a thin stream while whisking.

7. Cook for two to three minutes after the slurry goes in. Cornflour thickens almost immediately but it needs those couple of minutes to lose its chalky edge and turn properly glossy.

8. Taste and season. Slow cooker liquid is often already seasoned from the joint, so add salt cautiously and be more generous with the pepper. Pour it over the sliced beef.

Tips worth knowing

• Always skim the fat before you reduce. Reducing an unskimmed liquid concentrates the grease along with everything else and gives you a gravy that coats the mouth unpleasantly.
• Slake cornflour in cold water, never hot, and give it a stir immediately before pouring. It settles out of suspension in about fifteen seconds and you will end up with a lump if it goes in unstirred.
• Cornflour gravy goes thin again if you boil it hard for too long after thickening, so once it is where you want it, take it off the heat.
• If the liquid tastes weak, that is usually because too much water went into the slow cooker at the start. Reduce it harder, by a third or even a half, rather than adding a stock cube.

Keeping and reheating

Keeps four days in the fridge and freezes for three months. Cornflour thickened gravy can go slightly watery after freezing, so whisk it hard as it reheats and simmer for a minute to bring it back together.

Questions people ask