Whisk together the egg yolks, sugar and praline paste.
Remove the seeds from the vanilla pod.
Bring the cream, milk and vanilla up to a simmer.
Remove from the heat and whisk a little into the egg mix. Gradually pour in the rest of the cream until the sugar has completely dissolved.
Pour the mixture back into the saucepan and cook over a low heat until the mixture starts to thicken and coats the back of a spoon. Strain the mixture through a fine sieve and chill the mixture over ice. Once cool, pour the mixture into the ice cream machine and churn until chilled and firm. Place the finished ice cream in the freezer and keep until needed.
Preheat the oven to 180'C.
Blitz the pistachios in a food processor.
Dice the butter whilst cold and rub into the flour until the mixture resembles fine breadcrumbs. Mix in the caster sugar and the pistachios and bring the mixture together into a ball.
Roll into a log, wrap in cling film and refrigerate.
To cook the biscuits, cut the roll of shortbread into discs. Place on a baking tray and cook in the oven for 8 to 10 minutes or until golden brown at the edges.
«If you do not have an ice cream machine add 30ml of glucose to the mixture and freeze it in a tray. As the mixture freezes, whisk the mixture every 30 minutes to stop it freezing into a solid block.»