The combination of honey, chocolate and almonds just said Toblerone to me. For a crowd double the quantity and bake in two tins.
Preheat oven to 180°C. Grease and line a 23cm spring form cake tin.
Toast the almonds (for the topping) in the oven until golden – 5-10 minutes. Cool and roughly chop. Set aside.
For the cake: cream butter and brown sugar in an electric mixer fitted with the paddle attachment until pale and smooth. Add 6 egg yolks, one at a time, beating well after each addition.
Fold in the melted chocolate, vanilla and honey Set aside.
Whisk 6 egg whites and a pinch of salt until soft peaks form. Stir a third of the egg whites into the chocolate mixture to lighten then gently fold in the rest until just combined. Pour into the tin and bake for 25 minutes.
While the cake is baking, make the meringue: put the chopped almonds and chocolate chips in a small bowl, and set aside.
Whisk the 4 egg whites and vinegar until stiff peaks form. Add the caster sugar, a tablespoon at a time, beating the eggs back to stiff peaks after each addition. Once about half the sugar is in, slowly pour in the rest while beating. When the meringue is thick and glossy, fold in the potato starch and almond/ choc chip mixture.
After 25 minutes, remove the cake from oven and spread with the meringue. Return to the oven and bake until the meringue is lightly browned and crisp, 25 to 30 minutes.
Cool on a wire rack for 10 minutes, then carefully run a knife around the edge of the meringue and the cake to loosen, and open the tin. Cool before serving.