Grease a 1.2 liter/2 pt/5 cup pudding
basin or metal mould. Line the base with a circle of greaseproof
(waxed) paper. Beat together the remaining butter and the sugar until
light and fluffy. Melt the chocolate in a bowl over a pan of hot water
or in the microwave. Add to the butter and sugar with the egg yolk and
coffee, dissolved in the water, and the vanilla essence. Beat well.
Mix together the breadcrumbs and flour and fold half into the mocha
mixture with half the milk. Fold in the remaining crumb mixture and
milk. Spoon into the prepared basin or mould.
Cover with a double thickness of greased greaseproof (waxed) paper or
foil, twisting and folding under the rim of the basin or round the
edge of the mould to secure. If it doesn't seem very secure on a
fluted mould, tie round firmly with a piece of string. Steam for 2
hours. Loosen the edge and turn out on to a warmed serving dish. Spoon
a little Coffee Custard over and serve the rest separately.