2. For the base: Place butter, sugar and essence in a bowl. Beat until light and creamy. Fold in the flour and almonds. Press evenly into the tin. Place in the oven for 15 minutes until lightly browned. Remove and allow to cool.
3. For the filling: Place the eggs, yolk, sugar and sour cream in a blender. Whizz until smooth. Pour over the cooked base. Gently sprinkle the berries over. Place back in the oven for 35 minutes, until the centre is set. Remove and leave to cool in the tin.
4. Cut into pieces and serve with cream or yoghurt and extra berries.
