Preheat the oven to 180C/160C fan/gas mark 4. Grease and line the bases of 3 x 20cm/8-inch sandwich tins.
Whisk the egg whites to stiff peaks and set aside until needed.
Whisk the sugar and Stork with Butter until fluffy – it won’t be as fluffy as a regular cake mixture, because there’s a lot more sugar than fat here.
Slowly add the milk, whisking, then add the vanilla, flour and bicarb and beat to a smooth paste. Carefully fold in the egg whites, and divide as evenly as possible between the cake tins.
Bake in the preheated oven for 25-35 minutes, or until a skewer inserted into the centre comes out clean. Allow to cool completely in the tins.
For the buttercream, whisk the Stork with Butter until extremely pale, then add the icing sugar and whisk in for another five minutes – until almost white. Add a few drops of food colouring to achieve a very pale, egg-blue colour.
When the cakes have cooled, place one cake onto the cake card and spread the top with some of the buttercream. Repeat until you have 3 layers of cake sandwiched together with 2 layers of frosting. Chill for 20 minutes to firm.
Spread the remaining buttercream over the top and edges of the cake, getting it as neat and as sharp-cornered as possible.
Mix together the cocoa powder and vanilla extract until fairly liquid. Dip the toothbrush into the mixture and flick the bristles close to the cake so that the brown mixture spatters over the pale blue icing. Continue until the entire cake is covered and resembles the pattern of a speckled eggshell. Top with a pile of mini eggs.
Our thanks to Stork for providing this recipe. John Whaite has teamed up with Stork for their Sunday Bake service, which has recipes, tips and inspiration for bakers.