- Preheat the oven to 180 degC and line a shallow 30cm x 20cm tin with baking paper, or butter it lightly.
- Soften the butter. Cream the butter and sugar together until light then beat in the egg yolks and mix thoroughly.
- Add the lemon juice, then sift in the flour and baking powder and mix to a firm dough.
- Press the dough evenly into the prepared tin, and spread over the jam. You don't need a thick layer.
- Beat the egg whites until stiff then gently fold in the caster sugar and the coconut using a metal spoon.
- Spread carefully over the jam, again trying to keep an even thickness. Sprinkle with a little more coconut.
- Bake for about 25 minutes until the coconut is just turning a golden brown.
- Remove from the oven and cut into squares or fingers while it is still warm. Store airtight.
Makes 24 fingers.