Roast the hazelnuts for 15 minutes at 140°C (285°F), until they are evenly roasted all the way through. Let them cool completely. If you wish, remove the skins for a smoother, less rustic result. Personally, we remove about half of the skins to keep a more intense flavour. Blend for at least 5 minutes until you obtain a smooth, creamy paste. Pause occasionally if the food processor starts to overheat.
In a bowl, combine the sugar and skimmed milk powder to prevent lumps.
In a saucepan, whisk the hazelnut paste together with the milk and cream. Add the liquid glucose, then the sugar/milk powder mixture. Gently heat the mixture. It should not come to a boil, as this would cook the egg yolks in the next step.
Gradually pour the warm mixture over the egg yolks while whisking constantly. Return to the saucepan and cook until it reaches 82°C (180°F), stirring continuously. Do not let it boil.
Add the fleur de sel. Blend for 2 minutes until perfectly smooth. Strain through a fine sieve to remove any remaining hazelnut pieces.
Refrigerate the base for 12 to 24 hours.
Churn according to your ice cream maker’s instructions.
