It's creamy and sweet, a comfort blanket of the edible kind. White chocolate is the perfect ingredient for a dessert - so long as you cut it with something sharpThe ingredients are few: sugar, milk, cocoa butter and vanilla. That is it, really. No matter how skilfully you balance the ratio of those ingredients, white chocolate will always taste of childhood. As calming as a Murray Mint, as soothing as Mr Whippy and with enough milk to send us all gently to sleep, white chocolate is a comfort blanket of the edible kind.I used to think all white chocolate was the same - some just a sweet, candy version of the real thing. But I was wrong. Get a good brand - not too sweet and not too much vanilla - and you have something worth your time. A question of balance.
That said, even the best has a low cocoa butter content, less than half that of dark chocolate, and because of its high sugar content, this hybrid is more capricious than dark chocolate. It needs to be softened in a glass or china bowl over simmering water, as you would any cooking chocolate, but treated with even more care. Warmth rather than heat is what it needs. The trick is to switch the heat off as the pieces start to melt. The residual heat is enough to do the job. But the most important thing of all is not to stir. As the shards of white melt into a pool, tenderly push the unmelted ones below the surface instead.
The creamy sweetness of white chocolate requires a sharp addition if it is not to cloy. Dried fruits such as apricot and cherry work, as does lemon. But this week I found the perfect answer: passion fruit. So, to a crisp biscuit base I added soft fruit curd and a wafer-thin layer of white chocolate. A Milky Bar for grown-ups.
White chocolate and passion fruit slices
You will need a baking tin or shallow cake tin approximately 25cm by 20cm, lined with baking parchment or clingfilm. Use ginger or sweet oat biscuits for this, but not ginger nuts, which are too hard.
The finished slice will be soft and fragile. Serve with a fork. Serves 6.
For the passion fruit curd:
passion fruit 12
lemon juice and zest of 1
blood orange juice of 1
golden caster sugar 200g
butter 100g, cold and diced
eggs 3
egg yolk 1, lightly beaten
For the crumb crust:
white chocolate 100g
ginger biscuits 200g
For the top:
white chocolate 150g
To make the curd, halve the passion fruits then scrape their seeds and juice into a small sieve set over a bowl. Using a teaspoon, push as much of the juice and fibre as you can through the sieve until the seeds are almost dry. You will achieve a small amount of intensely sweet-sour juice. Discard the seeds. Add the juice and finely grated zest of the lemon and the juice of the orange.
Choose a small saucepan and a heatproof bowl that neatly fits the top of the pan. Pour in enough water to one-third fill the pan then put it over a moderate heat. Tip the juices into the bowl, together with the sugar and the diced butter. Stir till the butter has melted then add the eggs and extra egg yolk and stir till well mixed.
Leave the curd over the simmering water for about 10 minutes, stirring regularly but not necessarily continuously, until it feels thick and is a deep, opaque yellow. Remove the bowl from over the heat and set aside to cool. Refrigerate for as long as you can, preferably overnight. (The curd will keep covered and refrigerated for a week or more.)
Make the crumb crust. Break the white chocolate into small pieces into a heatproof bowl over a pan of lightly simmering water. It is best not to stir but to leave it to soften without touching. Crush the ginger biscuits to fine crumbs in a food processor. When the chocolate has melted, tip in the crumbs and mix lightly, then transfer to the cake tin, smooth gently, and leave in the fridge to set. Spread the curd over the top of the biscuit base and refrigerate for as long as you can, but a couple of hours at least.
For the top, break the white chocolate into small pieces and melt, as previously, over hot water. Trickle the melted chocolate over the surface of the curd and return briefly to the fridge to set crisp. Cut into six or more pieces. You can store the biscuits in the fridge for several days.
White chocolate and pistachio ice cream
Serves 6
full-cream milk 500ml
double cream 500ml
vanilla extract
egg yolks 4
caster sugar 4 tbsp
white chocolate 200g
pistachios 100g, shelled and finely chopped
Pour the milk and cream into a nonstick saucepan, add a few drops of vanilla extract and bring to the boil. Turn off the heat. Put the egg yolks and the sugar into a bowl and whisk until thick and creamy, then pour the hot vanilla cream over the egg yolks and sugar, stirring with a wooden spoon.
Rinse the pan, then pour in the custard mixture and place over a moderate heat. Stir almost constantly, but do not boil. When the mixture will coat the back of your wooden spoon, remove from the heat. If the custard shows any sign of curdling, plunge the saucepan into cold water and whisk furiously until all the steam has gone and the graininess disappeared.
In a pan over hot water, melt the white chocolate, then pour the custard into the chocolate and stir. Leave to chill, then pour into an ice-cream machine and churn until almost set. Add the chopped pistachios just as the ice cream is approaching readiness, then scoop the mixture into a cold freezer box and leave to freeze.
Email Nigel at nigel.slater@observer.co.uk. Follow Nigel on Twitter @NigelSlater
Photo: Nigel Slater: 'White chocolate is as calming as a Murray Mint.' Above: his white chocolate and passion fruit slices. Photograph: Jonathan Lovekin for the Observer