This recipe is best if made in a large glass bowl or oblong pan. The bottom layer is the baked cake mix, cut into squares and fit together as neatly as possible. Then, gently pour rum over the cake. Even more gently spread raspberry jam over the cake. Follow this by a healthy spreading of the custard or vanilla pudding. The next layer is whipped cream. Lastly, cover the whipped cream with the slivered almonds.