1 For the pistachio sponge: Preheat the oven to 170 degrees, or 150 degrees if using a fan oven. Grease three 20cm sandwich tins and line the base of each with a disc of parchment paper.

2 Cream the butter until pale and fluffy using a stand mixer, electric beater or by hand. Add the icing sugar and continue to beat until well mixed and smooth.

3 Add the eggs one by one, beating each one in until completely incorporated.

4 In a food processor, blend the pistachios to a fine crumb, taking care not to overmix as they will become oily if blended too much. Add the pistachios to the butter, sugar and egg mix, followed by the ground almonds.

5 Sift the cornflour and the baking powder into the mix to remove any lumps and mix until well combined.

6 Divide the sponge mix between the three prepared tins and bake in the preheated oven for 35-40 minutes until a skewer or tip of a knife inserted into the centre comes out clean.

7 Remove the sponges from the oven and leave to cool in the tins for 10 minutes before turning out on to wire racks to cool completely.

8 For the orange icing: Cream the butter until very pale and soft. Add a third of the icing sugar, beating well until fully combined. Repeat with the next third, mixing well, before adding the remaining sugar and continuing to beat for a few minutes until very pale – almost white – soft and creamy.

9 Add the orange zest and the juice of the orange. Add a tablespoon or two of milk to loosen the icing, adding a little more if needed. Set aside at room temperature until ready to assemble.

10 Place one of the sponges on a serving plate or cake stand and spread a few tablespoons of the icing on top. Repeat with the remaining sponges. Spread half of the remaining icing on the top and sides of the cake and scrape off the excess for the crumb coat. Leave to set for a few minutes, before repeating the process with the remaining icing. If there is any left, pipe a few buttercream bulbs on top of the cake. Garnish with edible flowers, if desired, and serve.