Heat a frying pan over medium-high heat and dry-fry the almonds for 2-3 minutes until golden and toasted, shaking the pan regularly. Remove from the pan and set aside.
Put a slice of chocolate sponge roll into the base of 6 glasses (about 350ml capacity) cutting the sponge to fit as necessary.
Drizzle with sherry or orange juice. Top with half the slices of prickly pear.
Top with the custard and whipped cream then the remaining prickly pear slices.
Top with toasted almonds and chill before serving.