Soak the cherries/cranberries and the sultanas in 50ml of the Amaretto overnight.
The following day line a 1.2-litre pudding basin with cling film (I used a fluted brioche mould here to get the nice ridges), leaving enough cling film hanging over the edges to fold over the top of the pudding and cover securely.
Slice the Genoise cake horizontally into three layers, setting aside one layer, and then cut both of the remaining layers into eight triangular slices.
Line the pudding basin with the cake slices, pointed ends first into the bottom of the basin. Make sure the whole basin is lined with the cake and there are no gaps, use any remaining cake to fill any spaces.