Lemon Curd Pudding

Preheat oven to 200C /400F / gas 6. Cream the butter, sugar and lemon rind in a mixing bowl. Add egg yolks and flour and beat in, then add the milk and 3 tablespoons of lemon juice and mix well. Whisk egg whites in a separate bowl until stiff then add the rest of the mixture. Fold well, but don't over mix it; otherwise the air will come out of the egg whites. Pour into a buttered ovenproof dish and stand the dish in a roasting tin or another ovenproof dish about 1/3 full of water (bain marie). Bake for 45 minutes or until the top is set and spongy and a nice golden colour.