This is a contemporary classic, invented by the great British chef Mark Hix, but I have taken the liberty of speeding up the sauce-making process, and (crucially) adding limoncello for an Italian touch. It gives a real edge to the ultra-rich white chocolate and, besides, I have been longing to do something with this particular combo ever since I saw the winning Joanne Wheatley create her Limoncello and White Chocolate Croquembouche on the BBC's cooking show The Great British Bake Off.
Now, white chocolate is much sneered at by those who take pride in their palate, considered )as the master baker Dan Lepard wrote in the British newspaper The Guardian) "the Big Mac of confectionery." Even if you take a similar line, and I'm afraid I have been known to do so myself, you are just going to have to believe me when I say that this recipe will challenge any prejudice you may be harboring. This is elegant and punchy at the same time; the depth of the limoncello and the sharpness of the berries completely defuse the unsophisticated and otherwise one-note richness of the white chocolate. All the same, if in doubt, I advise telling people it's a limoncello sauce, with no mention of the white chocolate, to begin with.
I am too impatient to melt the chocolate in a double boiler, and I do like an element of risk, but heating any chocolate can be tricky and white chocolate especially so; I would totally understand it if you were to prefer to make the sauce sensibly in a heatproof bowl suspended over a saucepan of simmering water, but you must make sure the base of the bowl doesn't touch the bubbling water beneath.
I love to serve this on a rimmed cake stand, but it could make more sense to make up individual portions in saucers or salad plates with a lip. I think it's important that, however you serve it, you try to keep the berries in a single layer, give or take.
What makes this fantastic for a last-minute, even impromptu, dinner-party dessert (with interesting Christmas potential) is that you can keep the berries in the freezer until needed. I suppose you could, in summer, use fresh berries, though you would lose the contrast between warm rich sauce and sharp icy fruit.
Put the heavy cream and 2 tablespoons of the limoncello in a small saucepan, and heat it until just about to come to a boil, but not actually boiling.
Take the pan off the heat and add the white chocolate, then swirl the pan about so that it is all submerged.
Take the berries out of the freezer and arrange them in a single layer in a dish or plate that has a small lip (so that the sauce doesn't drip off later). Sprinkle with the remaining 2 tablespoons of limoncello and leave for 5 minutes, during which time you can swirl your white chocolate pan about every now and again to help the chocolate melt into the lemony cream.
Using a rubber spatula, gently stir the chocolate-cream mixture, still off the heat, until it's smooth, then pour it over the berries and serve immediately.
Reprinted from Nigellissima. Copyright (c) 2012 by Nigella Lawson. Published by Clarkson Potter, a division of Random House LLC. All rights reserved.