Pre-heat the oven to 180'C.
Melt 30g of butter. Butter large, oven-proof coffee cups, ramequins or individual pudding moulds. Set aside until needed.
Zest and juice the lemons, and set aside until needed.
Cream 75g of butter with 100g caster sugar. The mixture will look rather lumpy, and not quite fluffy.
Whisk in each egg yolk completely before adding the next one.
Stir the baking powder and plain flour together.
Alternating between the flour, lemon juice and zest, and milk, gently fold into the butter mix in three parts.
In a separate bowl, whisk the remaing caster sugar and egg whites until the stiff peak stage.
Fold the egg whites into the batter. Do not worry if the batter looks curdled or split.
Divide the batter into the prepared moulds, and bake until the tops are evenly golden brown, about 20 minutes.
Unmould onto serving plates, and serve immediately. Alternatively, serve in the baking dish.
«This pudding can be baked in a larger baking dish and served straight from the dish.»
This dessert is a little bit of a mystery: a lumpy batter goes into the oven, and a moreish sponge comes out. To top it off, when the pudding is unmolded, a lovely sauce has miraculously formed under a thin layer of cake.