Preheat oven to 180°C/160°C fan forced. Grease a medium shallow ovenproof dish.
Spread one side of bread slices with butter; place buttered side up in prepared dish, sprinkle with sultanas.
Combine sweetened condensed milk, eggs, cream and vanilla in a medium bowl; whisk well. Pour over bread. Bake for 40 minutes or until just set. Serve dusted with icing sugar, if desired.
