CHOUX PASTRY
Heat the UHT whole milk, the water, the fine salt, the caster sugar and the unsalted butter cut into small cubes in a saucepan. Bring the mixture to the boil, then remove from the heat and quickly add the sifted flour. Whisk until the mixture forms a soft ball. Return the pan to the heat for 1 minute to dry out the mixture, continuously stirring with a silicone spatula. Transfer the mixture to the bowl of a mixer fitted with a flatbeater and weigh. Add water until the mixture weighs the same as it did before the previous step. Mix on a medium speed and gradually add the whole eggs. Allow the choux pastry to cool down to 30°C before working with it. Pipe 2 different sizes of choux using a piping bag fitted with a size 10 nozzle. Bake at 130°C - Damper open. Approximately 30 minutes depending on the size, followed by 15 minutes at 150°C.

VANILLA CRÈME PÂTISSIÈRE
Heat the UHT whole milk in a saucepan. Whisk together the caster sugar, egg yokes and whole eggs in a bowl, then add the corn starch. Pour some of the hot milk into the egg yolks. Transfer back to the saucepan and heat. Boil for 1 minute, then remove from the heat to add the cubed butter and the concentrated vanilla flavour. Cool rapidly to 3°C, then whiskthe crème pâtissière until smooth. Transfer to a piping bag fitted with a size 10 nozzle. Pipe into the pre-cut choux buns with a size 10 nozzle.

FONDANT ICING
Melt the cocoa butter, then stir in the fondant and the glucose. Heat the mixture to 35°C. Spread thinly between 2 Rhodoidsheets and transfer to the freezer. Cut out small fondant discs to fit the size of the choux buns and place on top of the filled choux buns.

DECORATION
Spread a thin layer of tempered chocolate onto the marble slab, then use a spatula to scrape chocolate shavings. Place the white chocolate shavings on the larger of the fondant-topped choux buns to form a ruff and sit the smaller choux bun on top.