Thane Prince’s baked lemon pudding

Method

1. Using an electric mixer, beat the butter and sugar for about 5 minutes until light in colour, scraping down the sides of the bowl occasionally. Add the egg yolks one at a time, then the lemon zest, beating until well mixed. Add the flour and beat until smooth. Heat the oven to 190°C/fan170°C/gas 5. 
2. With the motor running, very slowly add the lemon juice, then the milk and keep beating for a further 30 seconds.
3. Using an electric mixer (with a separate clean bowl and beaters), whisk the egg whites until stiff and glossy. Add to the batter and fold in with a metal spoon. 
4. Carefully pour the mixture into a greased 1.5 litre ovenproof dish. Put the dish in a deep roasting tin and pour in 2cm boiling water. Transfer to the oven and bake for 40-45 minutes until golden (see tip). Allow to cool slightly before serving.