Sift the flour into a bowl and add the sugar and lemon rind. Melt 25 g (1 oz) of the butter, then add to the flour with the whole egg, egg yolk and vanilla essence. Gradually whisk in the milk and water until smooth. Leave to stand for 30 minutes or longer.
Grease liberally 4 individual 200 ml (7 fl oz) metal pudding moulds with the remaining butter. Quarter the apricots and divide among the tins. Stand the tins on a baking sheet, then cook in a preheated oven, 190°C (375°F), Gas Mark 5, for 5 minutes.
Pour the batter quickly into the pudding moulds so that the mix sizzles in the hot butter. Bake for about 20 minutes until well risen and golden brown. Dust the tops with sifted icing sugar and serve immediately, as the puddings sink as they cool.