For the cake: Whisk the eggs with the sugar until light and airy. Fold in the flour, then mix in the melted butter.
Divide the batter between 4 cake tins of 16 cm diameter and bake at 200°C for about 17 minutes.
Leave to cool completely.
For the buttercream: Melt the chocolate over a bain-marie and set aside to cool.
Heat 800g sugar with the water to 115°C to make a syrup.
Whisk the egg yolks with 200g sugar until light. Slowly pour in the hot sugar syrup while continuing to whisk, until the mixture cools.
Whip the butter until very light and fluffy, then mix in the egg mixture.
Mix one quarter of the buttercream with the melted chocolate, then fold it back into the remaining buttercream and combine well.
To assemble: Cut one sponge horizontally into two thin layers. Stack three whole cakes, finishing with one thin layer on top.
Using an electric knife, carve the head and snout into the top two layers. Remove the head piece and carve legs into the bottom layers.
Spread buttercream between all layers and cover the entire cake with buttercream.
Cut out two ears from the remaining thin sponge layer using a glass and attach them to the cake, then cover with buttercream.
Cut out 5 round shapes from marzipan to form the snout and paws.
Cut out two small circles for the eyes and decorate them before placing on the cake.
Serve the cake immediately or keep in a cool place (not the fridge) for 2 days.
