Pre-heat the oven to 190 degrees C; grease a 20cm pie plate.
Roll the pastry into a round shape a little larger than the plate.
Cut a strip 1cm wide off the pastry and put round the edge of the plate with the cut edge outwards. Damp this strip with a little water and line the plate with the remainder of the pastry. Trim the edges and prick pastry with a fork.
Spread the centre with jam.
Put butter and sugar into a bowl and beat until white and creamy.
Beat the egg and lemon rind and add gradually to the creamed butter and sugar mixture.
Mix the flour and ground almonds. Fold the flour and ground almond mixture into the butter and sugar using a metal spoon, one spoonful at a time, adding the baking powder with the last addition of flour.
Spread this mixture over the jam.
Bake in the oven for about 30 mins until browned and thoroughly cooked.