Preheat the oven to 160C fan, 180C conventional, gas mark 4.
Make the pastry, wrap in cling film and chill for 30 minutes.
Roll the pastry out to 3mm thickness and line a 3.5 cm deep, fluted tin.
Bake blind for 15 minutes, brush with egg white, cook for a further 2 minutes and set aside to cool.
Cream the butter and sugar, gradually add the eggs and yolk then stir in the ground almonds and lemon zest.
Spread the jam over the cooled pastry base, then spoon the almond mixture on top, smoothing it and leveling the top. Scatter with the flaked almonds and cover loosely with foil.
Bake for 25 minutes at 170C. Remove foil and bake for a further 10 - 15 minutes.
