Prepare custard according to package directions, using 1 pint of milk.

Allow custard to cool completely, covering the surface with plastic wrap to prevent a skin from forming.

Slice sponge cakes into thick pieces.

Arrange the sponge cake slices in the bottom of a serving dish.

Scatter defrosted raspberries and macaroons over the sponge cake.

In a separate bowl, mix sherry with milk.

Pour the sherry mixture over the cake and fruit, adding more sherry as needed to thoroughly soak the cakes.

Sprinkle lemon rind over the soaked cake and fruit.

Distribute shredded almonds evenly over the top.

Carefully spread the cooled custard over the almond layer.

In a clean bowl, beat cream and egg whites together until stiff peaks form.

Sweeten the whipped cream mixture to taste with sugar.

Pile the sweetened whipped cream on top of the custard.

Refrigerate for at least 30 minutes before serving.