Make the brioche dough. Place the flour and salt into the bowl of the Kenwood kMix stand mixer fitted with dough hook andblend together. Then add the yeast and Billington’s Golden Caster Sugar and blendthat through too. Beat the eggs with the Just Milk, and add to the bowl. Knead on a medium speed for 15 minutes, until the dough is extremely stretchy.
Slowly add the butter piece by piece, mixing still on medium. It should take around 5 minutes to incorporate the butter. When done, allow the mixer to continue for about 5 minutes, until the dough is smooth, silky and very stretchy.
Place the dough onto a Pyrex Baking Tray, and wrap tightly with cling film. Place into the fridge overnight, or for at least 12 hours.
Place the Just Milk and Nielsen-Massey Vanilla Bean Paste into a medium saucepan over a medium heat. Allow it to come to the boil. As the milk heats, quickly whisk together the egg yolks and sugar until the sugar dissolves, then whisk in the cornflour. Pour half of the boiling milk onto the egg mixture and whisk immediately and rapidly. Then pour this back into the pan with the remaining half of the milk and place back onto the heat, whisking constantly until the mixture comes to the boil and becomes very thick. When thick enough to coat the back of a wooden spoon – removing the pan from the heat to test – scrape the Crème Pâtissière onto a large plate and immediately cover the surface of it with cling film. Allow to cool completely and refrigerate until needed.
When the brioche dough has rested overnight, flour the worktop and then roll out into a large disk of about 10 inches in diameter. Remove the Crème Pâtissière from the fridge and with a wooden spoon vigorously knock the Crème Pâtissière back – beating it to a smooth custard.
Spread or pipe the Crème Pâtissière onto the brioche disk, leaving a good inch around the edge. Peel, core and quarter the apple, then slice it very finely – I use a mandolin slicer. Place this onto the Crème Pâtissière in a spiral pattern then halve the blackberries and dot them around. Gently crimp the edges of the brioche by pulling a little brioche outwards, then sticking it onto the edge on the left.
Preheat the oven to 200C/180C fan/gas mark 6. Allow this brioche pizza to rest until the edges have puffed up and almost doubled in size. Egg wash the edges and bake in the preheated oven for 25-30 minutes, or until the exposed brioche is a deep golden colour. Heat the apricot jam with 3tbsp water, pass through a sieve and glaze the hot, freshly baked brioche. Cool then finish with a generous dusting of Billington’s Golden Icing Sugar.