Rich Chocolate Cake

Preheat the oven to 325u0b0F. Line the bottom of a 9-inch springform pan with parchment paper. Melt 5 oz chocolate in a heatproof bowl set over a pan of simmering water. Allow to cool slightly.
Beat the egg whites in a large bowl with an electric mixer until stiff peaks form. Gradually beat in 1/3 of the granulated sugar. Beat in the butter, remaining sugar and a pinch of salt. Beat in the egg yolks, one at a time. Stir in the melted chocolate. Sift in the flour and fold in loosely. Spoon into the prepared pan, smoothing top.
Bake for 40-50 mins, until a toothpick inserted into center comes out clean. Cool in pan for 10 mins. Remove from pan; cool completely on a wire rack.
Cut the cake in half horizontally by inserting a knife into the middle and rotating the cake around it. Heat the jam in a small saucepan and strain through a sieve. Spread 1/3 of the jam on bottom cake layer. Cover with top cake layer. Spread with the remaining jam.
Knead the marzipan and powdered sugar. Roll out the marzipan to a 12-inch circle on a work surface dusted with powdered sugar. Place on top of the cake and press down gently. Trim any excess marzipan.
Melt 4 oz of the chocolate in a heatproof bowl set over a pan of simmering water. Add the coconut oil and remaining 3 oz chocolate and stir until melted. Spread evenly over the cake. Let stand until chocolate is set. Decorate with chocolates.