Blood Orange Sorbet with Whisky

STEP 1: MAKE THE SORBET BASE

Warm 150 ml of the blood orange juice with the caster sugar, liquid glucose, grated blood orange zest and fine sea salt, stirring until everything has dissolved. Do not let it boil: blood orange loses its perfume quickly under heat. Off the heat, stir in the remaining juice and the lemon juice, then chill thoroughly, ideally overnight. A rested base churns finer.

STEP 2: CHURN AND FREEZE THE SORBET

Strain the chilled base through a fine sieve, then churn in an ice cream maker until it holds a soft scoop. Transfer to a shallow container and freeze for 4-6 hours, until firm but not solid. Without a machine, freeze in a shallow tray and fork through the mixture every 30 minutes for about 3 hours; the crystals are coarser but the flavour is identical. Move the sorbet to the fridge 10 minutes before serving so it yields to a spoon without collapsing.

STEP 3: REDUCE THE SPARKLING WINE

Put the sparkling wine in a wide pan with the strip of blood orange zest and reduce over a medium heat to about 200 ml, roughly half. This is the change that matters most. A foam is mostly air, so an unreduced wine base has nothing left to say once it has been aerated.

STEP 4: FINISH AND CHARGE THE ESPUMA BASE

Off the heat, whisk in the caster sugar and the softened gelatine until fully dissolved, then discard the zest. Cool to room temperature and stir in the cold Scotch whisky, the lemon juice and the salt; the whisky goes in cold and late so its aromatics survive. Taste the base now: it should read slightly too strong, too sweet and too sharp on a spoon, because a foam always reads flatter than the liquid it came from. Strain into a 0.5 litre cream whipper, charge with one N2O cartridge, shake well and refrigerate for at least 2 hours, then shake again before dispensing. Without a siphon, whisk 150 ml of the cooled base with 40 g pasteurised egg white to soft peaks and spoon it over; the body is lighter and the life shorter, so serve at once.

STEP 5: MARINATE THE CHERRIES (OPTIONAL)

Warm the Scotch whisky with the caster sugar and the strip of orange zest until the sugar dissolves, then pour over the stoned cherries and leave to cool. Refrigerate for at least 4 hours, or up to a week, and drain them well before use: wet cherries dropped into the glass will thin the foam sitting above them.

STEP 6: ASSEMBLE AND SERVE

Chill six martini glasses hard, half an hour in the freezer. If you are using the cherries, drop three or four drained ones into the base of each glass. Add a generous scoop of sorbet, then thread half a teaspoon of the extra virgin olive oil over it, enough to catch the light without pooling. Dispense the espuma so it domes above the rim, add a second half-teaspoon of olive oil over the foam, and grind long pepper over the surface at the table. Serve immediately, with a spoon: every minute the foam stands costs it aroma. If long pepper is hard to find, reach for cubeb or grains of paradise rather than black pepper, which reads as savoury here.