Preheat oven to 180 degrees C

Place the butter, zest and sugar in a bowl and beat until pale and creamy

Add the egg yolks, one by one beating well after each addition

Fold through the flour and add the milk in a steady stream, whisking lighting to combine

Add the lemon juice and salt and mix to combine (the mixture will look slightly curdled)

Place the egg whites in a clean bowl and whisk until stiff peaks form

Using a large metal spoon, fold the egg whites through the batter

Pour the batter into 4 x 250ml greased ovenproof ramekins and bake for 15 minutes until lightly browned

While the puddings bake, mix the yoghurt with the zest, sugar and juice and set aside

Serve the pudding with a good dollop of yoghurt and some berries if preferred