Step 1

Preheat oven to 160°C. Grease and line base of pans with baking paper.

Step 2

Combine chocolate and the water in a medium saucepan over low heat; stir for 4 minutes or until smooth. Remove from heat; cool slightly.

Step 3

Beat butter and sugar in a large bowl with electric mixer until light and fluffy. Add eggs one at a time, beating until combined.

Step 4

Stir in chocolate mixture, ground hazelnuts, sifted flour and cocoa in two batches. Divide cake mixture evenly into pans.

Step 5

Bake cakes 1¼ hours or until cooked when tested. Stand cakes 5 minutes; turn top-side up onto wire racks to cool.

Step 6

Make coffee mousse.

Step 7

Dissolve gelatine in a heatproof jug with the boiling water; stir until gelatine dissolves. Combine coffee with the hot water in a heatproof jug. Add coffee mixture to gelatine mixture with marsala; stir to combine. Set aside.

Step 8

Beat egg yolks and sugar in a small bowl with electric mixer until pale and thick. Place mascarpone into a large bowl; gently fold in egg yolk mixture.

Step 9

Beat cream in a small bowl with electric mixer until soft peaks form; fold into mascarpone mixture.

Step 10

Beat egg whites in a clean small bowl with electric mixer until soft peaks form; fold egg whites into mascarpone.

Step 11

Fold cooled coffee mixture into mascarpone mixture.

Step 12

Trim cakes; split cakes in half. Secure one layer to cake board with a little mousse. Make a firm paper collar around cake using three layers of baking paper; staple paper to join.

Step 13

Pour a third of the mousse over cake; smooth with a spatula. Continue layering with cake and mousse. Place cake in fridge for 6 hours or overnight.

Step 14

Carefully remove paper collar from cake; dust cake with sifted cocoa powder. Trim flowers to fit cake. Wrap stems in florist’s tape; arrange flowers and cake topper on cake.