Preheat the oven to fan 180C/conventional 200C/gas 6 and grease four 150ml dariole moulds or heatproof teacups with the lactose free butter – this will help you turn out the puddings and add a touch more flavour.
Mash the banana in a mixing bowl, using a fork. Beat in the eggs and vanilla extract, then stir in the gluten free breadcrumbs, sugar and lactose free milk.
Spoon the mixture evenly into the moulds or teacups. Arrange them in a small roasting dish, and then pour in enough hot water to reach about halfway up their sides.
Bake uncovered, for 35 minutes, until set. Cool for a few moments, then turn out onto small serving plates.
Drizzle a tablespoon of maple syrup over each pudding, then finish with a teaspoon of lactose free cream and a sprinkle of freshly grated nutmeg, if you like.