Curry Leaf and Mustard Seed Gravy

A tarka, or tempering, is spices bloomed in hot fat and poured over a dish at the last moment. The same technique makes a very good gravy base, because mustard seeds and curry leaves both need hot oil to give up what they have. This is a bright, aromatic gravy for roast chicken, lamb chops or a plate of roast potatoes and greens.

Ingredients

Makes about 450ml, enough for four plates

• 2 tbsp rapeseed or coconut oil
• 1 tsp black mustard seeds
• 12 fresh curry leaves or 15 dried, though fresh is much better
• 1 small onion chopped fine
• 1 clove garlic grated
• ½ tsp ground turmeric
• 1½ tbsp plain flour
• 500ml (18fl oz) hot chicken stock
• 1 lime the juice of half, to finish
• salt and black pepper to taste

Kit

• Saucepan with a lid
• Balloon whisk
• Measuring jug

Method

1. Heat the oil in a saucepan over a medium high heat until it shimmers. Add the mustard seeds and put the lid on straight away, because they will jump. Listen for the popping, which takes about thirty seconds and slows down when they are done.

2. Take the lid off, drop in the curry leaves and stand back. They will spit and crackle for ten seconds and go translucent, and the smell that comes off them is the whole point of the recipe.

3. Turn the heat down to medium, add the onion and cook for six minutes until soft. Add the garlic and turmeric and cook for forty seconds, stirring constantly so the turmeric does not catch and go bitter.

4. Stir in the flour and cook it for a minute. The pan will be a strong yellow at this stage, which is fine, the stock brings it back towards a normal gravy colour.

5. Add a third of the hot stock and whisk hard until smooth, then the rest in two goes. Bring it to a gentle simmer.

6. Simmer for six minutes, whisking now and then, until it thickens enough to coat a spoon and the spices have settled into the liquid.

7. Take it off the heat and add the lime juice. Taste and season. The lime is not optional, without it the gravy tastes muddy and flat rather than bright.

8. Serve as it is, with the curry leaves left in. They are edible and people can push them to the side of the plate if they would rather.

Tips worth knowing

• The mustard seeds must actually pop. Unpopped they taste raw and bitter, and popped they turn nutty. Lid on, medium high heat, wait for the noise to slow down.
• One teaspoon of mustard seeds in 500ml is right. Two makes the gravy noticeably bitter and slightly gritty, and no amount of lime will fix it.
• Fresh curry leaves are worth hunting down and they freeze beautifully in a bag, straight from frozen into hot oil. Dried ones are a shadow of the same thing.
• Curry leaf is not the same as curry powder and there is no substitute for it. Leave it out and make a mustard seed gravy rather than trying to swap in something else.

Keeping and reheating

Keeps three days in the fridge and freezes for three months. The lime fades, so add a fresh squeeze after reheating. Warm it gently with a splash of stock and whisk it back together.

Questions people ask