Lightly butter a 5-cup capacity charlotte mould or china soufflé dish, then dust well with caster sugar, tapping out excess.
Gently melt butter in a small pan, remove pan from heat, add flour and stir until smooth. Cool. Melt chocolate in the milk over gentle heat, stirring until smooth and steamy. Pour onto butter and flour and stir until smooth.
Beat in caster sugar then 1 whole egg and 1 yolk, putting egg white in a greasefree bowl. Lightly beat egg white until soft peaks form, then fold through mixture with a large spoon.
Pour mixture into prepared dish, cover top with baking paper, then tinfoil and steam in a double boiler (or use a steamer) until set about 45 minutes. Rest in dish for 5 minutes, then remove covering and loosen pudding from sides. Cover with a plate, invert, wait until you hear it plop out, then remove dish.
Melt chocolate and cream together, either over a gentle heat in a saucepan or in a microwave. Beat until smooth. Pour over pudding. Serve with cream.
From Taste magazine, August 2010.