• 50 g (1 oz) butter
• 1 tablespoon groundnut or sunflower oil
• 2 teaspoons ground coriander
• 1 teaspoon ground cumin
• 1 teaspoon ground cinnamon
• 5 cm (1 in) piece fresh ginger, peeled and chopped finely
• 3 large cloves garlic, chopped finely
• 175 g (6 oz) mushrooms, chopped finely including stalks
• 2 tablespoons tomato puree
• 125 ml (4 fl oz) water
• 4 tablespoons lemon juice, strained
• 300 ml (14 pint) double cream
• Salt
• 2–4 pinches cayenne pepper
• Handful of fresh coriander or mint leaves, chopped roughly

Melt the butter and oil in a heavy-based saucepan over a medium heat, then add the ground coriander, cumin and cinnamon and the chopped ginger and garlic. Stir the spices for a minute or so and then add the chopped mushrooms. Toss around until beginning to soften, and then add the tomato puree, the water and the strained lemon juice.

Mix the contents of the saucepan thoroughly and bring to the boil, then lower the heat and simmer very gently in the open pan, stirring now and then, for 15–20 minutes. Bring to the boil again (if the mushroom mixture is very liquid bubble for a few more minutes to reduce it slightly) and add the double cream.

Stir and bubble the mixture for about 2 minutes, then remove the saucepan from the heat. Add salt and cayenne pepper to taste and stir in the roughly chopped coriander or mint leaves just before serving.

If you want to make the sauce well in advance, which you can, add the fresh herbs after you have reheated it gently.