Simmer gooseberries and 150ml elderflower cordial in a pan until soft and pulpy.
Allow the fruit mixture to cool completely and place in a serving dish.
Heat 150ml milk in a saucepan until it nearly reaches boiling point.
Whisk egg yolks, 1 tsp arrowroot, and 30g sugar in a jug.
Pour hot milk into the egg mixture while mixing well.
Return custard to the pan and heat gently until thickened without boiling.
Strain the custard into a bowl and leave to cool.
Whip 150ml double cream until it reaches the same consistency as the gooseberries.
Fold the cream and then the cooled custard into the gooseberries to create a marbled effect.
Decorate the dish with fresh elderflowers before serving.