Instructions

To make the cake:

1. Preheat the oven to 325 degrees F. Butter the bottom and sides of 3 9inch cake tins. Line the base with parchment paper and dust the sides with flour, tap out any excess.
2. Spread the nuts onto a baking tray and toast for 10-12 minutes until lightly browned. Leave to cool completely. Increase the oven temperature to 350 degrees F.
3. In a food processor, grind the graham crackers to crumbs. Transfer to a bowl and set aside. Add the toasted nuts to the processor (no need to wash) and add ¼ cup of sugar. Pulse until the nuts are finely ground, but do not blitz too much or else it will form a paste. Add the nuts, graham cracker crumbs and grated chocolate together in the bowl and mix.
4. In a large bowl, whisk the egg yolks and ½ cup of sugar using an electric mixer until well blended. Add the oil and vanilla slowly, beating until ribbons begin to form on the surface of the mixture. Then, fold in the chocolate nut crumbs.
5. Place the egg whites in a clean bowl and beat until thick and foamy. Gradually add the remaining ½ cup of sugar, continuing to beat until the whites form stiff peaks. Fold a third of the egg whites into the yolk mixture and mix well to slacken the mix. Sift over the flour, spice and baking powder and fold in. Gently fold in the rest of the egg whites until no streaks remain but do not over mix.
6. Divide the batter between the three pans and bake for 25-30 minutes until a toothpick comes out clean. Let the layers cool in the pans for 10 minutes before turning out onto a wire rack to cool completely.

To make the rum syrup:

1. Combine the sugar and water in a small saucepan. Place over a medium heat, stirring until the sugar dissolves. Remove from the heat and add the rum. Allow to cool before using.
2. To make the creme chantilly:
3. Combine the cream, sugar and vanilla in a chilled bowl and whip until the cream is stiff but not too thick or buttery.

To assemble:

1. Place a layer on a cake stand, flat side up.
2. Sprinkle it with a third of the rum syrup and let it all soak in for 1-2 minutes.
3. Spread ¾ cup of crème Chantilly over the top, right to the edge.
4. Repeat with the remaining layers, letting the syrup soak in before adding the crème.
5. Use the rest of the crème to cover the sides of the cake.
6. Decorate the top with dark chocolate curls, if desired.