- Beat egg whites in a large bowl until stiff but not dry.
- In separate bowl, stir together sugar, flour and salt. Whisk in lemon zest, lemon juice, butter or margarine, milk, yogurt and egg yolks.
- Gently fold whipped whites into lemon mixture.
- Pour into greased 1 quart (1 L) baking dish. Place baking dish in a shallow pan of hot water so that the water rises 1 inch (2.5 cm) up the sides of the baking dish.
- Bake in a preheated 180°C (350°F) oven until top is lightly browned, about 35 to 40 minutes. Serve warm or cold.
Tip:Â Sprinkle pudding cake with icing sugar or top with a dollop of whipped cream.