Nigel Slater’s midweek treat: white chocolate and pistachio ice-cream

Serves 8. Ready in 2-3 hours.

Pour 500ml of both full fat milk and double cream into a saucepan, add a few drops of vanilla extract and bring to the boil. Turn off the heat. Put 4 egg yolks and 4 tbsp of caster sugar into a bowl and whisk until thick and creamy, then pour the hot vanilla cream over the egg and sugar mixture, stirring with a wooden spoon.

Rinse the pan, then pour in the custard and place over a moderate heat. Stir almost constantly, without allowing the custard to come to the boil. When the mixture will lightly coat the back of your spoon, remove from the heat. If it shows any signs of curdling, put into a bowl, plunge into ice cold water and whisk furiously until it looks stable.

Place a pan of water on to boil and find a heatproof bowl that will fit neatly into it, without touching the water. Break 200g of white chocolate into small pieces, put them in the bowl and leave to melt. Do not be tempted to stir them. Once they are melted pour the custard over and stir.

Leave the custard to cool, then pour into an ice-cream machine and churn until almost set. Chop 100g of shelled pistachios and add them to the ice-cream, churning briefly before transferring to a freezer box and storing in the deep freeze for a couple of hours.

• I pour the custard into the melted chocolate with the bowl still over the hot water, then stir to make sure the chocolate and custard are thoroughly combined.

• It is important to ensure the custard is cool before pouring into the ice-cream churn. Cooling it in a bowl set over ice cubes speeds up the process.

• You may want to keep a few pistachios for decoration. At this point in the year, especially if we are eating in the garden, I may add an edible flower or leaf to the dish. Scented pelargoniums are charming here, as might be a small fig leaf.