Preheat the oven to 180 degrees celcius
Grease 6 ramekins with some melted butter
In a large bowl whisk together the egg yolks, milk, lemon zest, lemon juice and butter. Add the flour and sugar and whisk until smooth
Using an electric or stand mixer beat the egg whites until soft peaks form. The peaks should curl when you lift the beaters out of the bowl. I did beat mine until it was stiff, in error,and it worked fine.
Spoon a 1/4 of the eggs whites into the cake batter and using a rubber spatula fold it in until mixture is smooth. Add in the remaining eggs whites and do the same. The batter should be light, foamy and liquidy
Place the ramekins in a large baking dish. Fill the ramekins with the cake batter, almost to the top. Pour some room temperature water into the large baking dish.
Place the dish with the ramekins into the oven and bake at 180 degrees celcius for 30 minutes or until cakes are puffy and lightly golden on top.
Remove ramekins from the baking dish and let it cool for 20 minutes before serving. They will sink a bit but that's perfectly ok
Dust with icing sugar and serve with berries if desired