Preheat the oven to 200C/400F. For the bread and butter pudding, in a bowl mix the egg yolk with the cream, then layer a greased oven proof mold with the bread. Pour over the egg mixture.
For the toffee sauce, heat the butter and sugar together in a pan until golden. Add the cream and take off the heat. Pour this mixture over the pudding, then place into the oven for 10 minutes or bake until set. After backing let stand 15 minutes. Serve the bread and butter pudding on a plate with a dusting of icing sugar. but I always prefer to serve with extra toffee sauce.