This recipe is by Ferran Adrià - the inventor of the espuma and one of the most influential chefs today.
Peel the potatoes, cook in salt water until tender and strain (do not puree!). Mix together with hot milk, potato water and butter. Season with nutmeg and salt and Pour into the 0,5 l iSi Whipper while hot (CAUTION: The outer cover becomes very warm - use heat protection when you take the bottle in your hand).
Screw on 1 iSi Cream Charger and shake vigorously. Serve immediately or keep the iSi Whipper warm at a constant temperature of max. 75 °C in a bain-marie.
CAUTION: Do not place the iSi Thermo Whip or iSi Thermo XPress Whip in the bain-marie or water bath!
The puree is supple and is very easy to gratinate. Particularly exquisite: season with truffle oil.
If using a 1 l iSi Whipper, double the ingredients, screw on 2 iSi Cream Chargers one after the other. Shake vigorously after attaching each Charger. Halve the ingredients if using a 0.25 l iSi Whipper.
Recipe by Ferran Adrià, Restaurant El Bulli, Roses (Spain)