Filling:
In a small pan, place 1/4 cup lemon juice, 1/2 cup sugar, 60gm butter and 1 beaten egg.
Stir over gentle heat to thicken.

Cake:
Sift 1 cup SR flour, add 1/2 cup sugar.
Rub in 60 gms butter
Stir in 1 large beaten egg to make a stiff dough
Press into a lined small tin, keeping back about a quarter of the mixture
Pour over hot filling
Crumble small pieces of reserved dough on top (squashed in the hand makes it easier to handle)
Bake at 180 deg C for 30-35 minutes