For the choux buns:

Bring the water, butter, salt and sugar to the boil. Remove from the heat and mix in the sifted flour. Return to the heat for a few minutes, quickly stirring and cook until the dough forms a single lump.

Allow to cool enough to keep the eggs from cooking, and stir them in gradually using a strong wooden spoon.

Transfer the dough to a piping bag and pipe into dollops, in three sizes - tablespoon, teaspoon, hazelnut - a dozen of each.

Bake in a preheated oven at 180C for 25-35 minutes (the smaller buns will cook more quickly so check).

Remove from the oven, make a small piercing in the bottom of each bun to allow steam to escape.

For the chocolate creme patissiere:

Heat the milk and add the chocolate, stir to melt.

Whisk the egg yolks, flour, sugar, cocoa and cornstarch to a smooth mixture.

Add half the hot chocolate to the bowl, a bit at a time, stirring all the time.

Add this back to the rest of the hot milk, stirring over a gentle heat for a few minutes until thickened to a custard.

Remove from heat and chill.

Once cooled, spoon into a pastry bag and pipe into the centre of the large and medium pastry balls.

To decorate:

Sieve the icing sugar into a bowl, adding the vanilla and milk until you reach the desired consistency.

Separate into three small bowls, and add food colouring: lavender (large buns), pale green (medium buns), and pink (small buns).

Dip each pastry into the icing to its midline. Place on a tray and leave to dry.

Decorate with filigree of white chocolate.

Place a dollop of pale blue icing atop the large ball, place the medium on top and press to stick in place.

Repeat with the small ball.

Make a small buttercream star on top and place a single cocoa bean onto the star as a garnish.