In a large bowl, whisk together 1 cup (250 mL) sugar with flour and salt.
In a separate large bowl, whisk milk, butter and egg yolks. Stir milk mixture into flour mixture. Whisk in lemon rind and juice. Set aside.
In a separate bowl, beat egg whites until soft peaks form. Add remaining ¼ cup (50 mL) sugar, 1 tbsp (15 mL) at a time, until stiff but still moist peaks form.
Fold beaten whites into lemon mixture to ensure the batter stays light and fluffy.
Scrape mixture into a greased 8-inch (2 L) square glass baking dish. Place glass baking dish in a larger shallow pan. Pour in enough hot water to come halfway up sides of glass baking dish. Bake in 350°F (180°C) oven until cake is light golden, fluffy and springs back when touched lightly in center, about 45 minutes. Remove from water bath and let glass baking dish cool on a rack for 10 minutes.
Spoon into serving dishes. Garnish with whipped cream.
Tip: For this recipe you can forget the fork test to see if the cake is cooked... this one is mean to be soft and gooey on the bottom. This layer is creamy, smooth lemon pudding. To ensure it is cooked, the top should be light golden, fluffy and should spring back when touched lightly in the centre.
Tip: Put icing sugar in a small sift and tap gently over top of cake.