Roll out the pastry (paste) and use to
line a greased 30 x 20 cm/12 x 8 in Swiss roll tin (jelly roll pan).
Spread with the jam. Whisk the egg whites until stiff, then gently
fold in the ground almonds, sugar and almond essence. Spread over the
jam and sprinkle with the flaked almonds. Bake in a preheated oven at
180°C/350°F/gas mark 4 for 45 minutes until golden and crisp. Leave to
cool, then cut into squares.