1

Put the blueberries into a saucepan with 3 tbsp cold water. Heat gently for 2-3 minutes until the juice begins to run. Cool slightly, then mix gently with the strawberries, raspberries and blueberries. Share the fruit between 4 serving dishes.

2

Using an electric whisk, beat the egg yolk with the sugar in a heatproof bowl until very pale in colour and light in texture. This will take about 3-4 minutes.

3

Add the grape juice and white wine and continue to whisk, standing the bowl over a saucepan of gently simmering water until the sauce thickens and is very light and foamy. Remove from the heat and whisk for a further 30 seconds or so.

4

Serve at once, spooning the sauce on top of the fruit.