For the meringue, heat the oven to 100°C (fan). In a mixer, whip the egg whites until foamy and dry, then add the sugar a spoonful at a time until it's all used and the meringue is thick and glossy, and you can't feel the sugar when you rub a bit of the mixture between your fingers.
Add a little yellow food coloring to the mixture. Place the meringue in a piping bag fitted with a round nozzle and pipe small triangle shapes onto baking paper; add a smaller triangle on top of some to create larger chicks. Bake for 30–35 minutes or until dry to the touch. Leave to cool.
When they have cooled, draw eyes, beak and feet on the meringue with an edible pen to make them look like little chicks.
Heat the oven to 160°C (fan) and fill a cupcake tin with 12 paper cases.
Place the egg, vanilla, buttermilk, cooled coffee and vegetable oil in a bowl and mix well. Add the flour, cocoa powder, sugar and bicarbonate of soda in a large bowl, then fill the paper cases up to 3/4 full. Push egg crème into the center and bake for 20–25 minutes or until a toothpick inserted comes out clean. Leave to cool.
While the cakes are baking, make the ganache by adding the chocolate spread and chocolate pieces to a bowl. Heat the cream until steaming, then pour over the chocolate. Leave for a few minutes to melt, then mix vigorously until smooth and glossy. Refrigerate to firm up.
Place the ganache in a piping bag and pipe a swirl onto each cake.
Decorate with small chocolate eggs and the meringue chicks.