Line a 7-in. flan ring or a pie-plate with the pastry. Place a good layer of raspberry jam on the bottom. Cream together the butter and sugar till thick and white. Beat in the egg and add the ground almonds and cake-crumbs and a few drops of almond essence. Spread the mixture on top of the jam and bake in a fairly hot oven (400° F., Gas 6) for about ½ hr.
Sprinkle icing sugar on top and serve hot or cold.