Traditional Steamed Treacle Sponge Pudding with Custard vs Classic Boston Cream Pie

Both desserts rely on the same blend of milk, egg yolks, vanilla and cornflour to make a thickened cream, yet they use it in opposite ways. The treacle sponge is steamed for up to two hours in a basin spread with golden syrup, then turned out so the syrup coats the top, and served warm with a pourable vanilla custard. The Boston cream pie instead bakes two light sponge layers, fills them with chilled, set pastry cream, and finishes with a glossy chocolate glaze made with cream and corn syrup, served cold.