For the filling, place the ProZero Chocolate flavour, butter, custard powder, sugar and vanilla essence into a small saucepan, over a gentle heat and stir well.
Keep stirring until the mixture starts to simmer and is thickened.
Take off the heat, then pour into a container and use a hand-held blender to blend for 30-40 seconds and leave to cool.
Once cooled, cover and place in the fridge to chill for 3-4 hours, or preferably overnight.
Once chilled, the custard will softly set.
Once set, the custard can be whipped to form a light and airy consistency by using a hand-held electric whisk.
Preheat oven to 190°C/fan 170°C/ gas mark 5.
For the pastry base, rub the Fate Low Protein All-Purpose Mix, margarine and sugar together in a mixing bowl, until it resembles coarse breadcrumbs.
Add the water to the Fate mixture and mix to form the pastry dough.
Leave to rest for 10 minutes.
Dust a clean work surface with Fate Low Protein All-Purpose Mix and knead the pastry for 1 minute, until smooth.
Using a rolling pin, roll the pastry out between two pieces of grease proof paper to a 28cm diameter circle.
Using a rolling pin, lift the pastry into the pastry dish and press the pastry around the edge using your thumb.
Cut the excess pastry off the sides of the dish and using a fork, prick the pastry base.
Line the inside of the base with greaseproof paper and add some baking beans or dried beans or lentils. Bake in the oven for 10 minutes or until golden brown.
Remove the baking beans, set aside and allow to cool.
Spoon the cooled ‘Chocolate’ custard mixture into the pastry dish and allow to cool in the fridge for 20 minutes, then sprinkle with the grated Vitabite.
Serve with low protein ‘cream’ or ice ‘cream’ (see www.vitafriendspku.co.uk/pku/recipes).
YOU WILL NEED A 24CM LINED PIE DISH, HAND-HELD ELECTRIC BLENDER AND A HAND-HELD ELECTRIC WHISK.