200 gm rhubarb, coarsely chopped210 gm raw caster sugar, plus extra for moulds50 ml dessert wine3vanilla beans, split and seeds scraped580 ml milk50 gm (1/3 cup) plain flour20 gm butter, plus extra for greasing4egg yolks2eggwhites250 ml (1 cup) pouring creamFor dusting:pure icing sugar
Rinse rhubarb in a colander, shaking off excess water, then combine in a saucepan with 75gm sugar, dessert wine and 1 vanilla bean and seeds. Stir over medium-high heat until sugar dissolves, bring to the boil and cook, stirring occasionally, for 12-15 minutes or until rhubarb is soft and mixture is jammy. Remove vanilla bean and set aside.
Preheat oven to 180C. Combine 250ml milk and 1 vanilla bean and seeds in a saucepan and bring just to the boil over medium heat. Meanwhile, combine 60gm sugar, flour and 80ml milk in a bowl and whisk until smooth. Remove milk mixture from heat and remove vanilla bean. Pour over flour mixture, whisk to combine and return to pan. Whisk over medium heat for 1 minute or until thick, remove from heat, add butter and mix to combine. Stand for 5 minutes, add 2 yolks and whisk to combine, then add ½ cup rhubarb mixture and fold through.
Whisk eggwhites and a pinch of salt until soft peaks form, scatter over 20gm sugar and whisk until firm peaks form. Fold one-third of eggwhite mixture into rhubarb mixture until just combined; fold in remaining eggwhite. Divide among four buttered and sugared 1 cup-capacity metal dariole moulds, place in a roasting pan and fill halfway up sides with hot water. Bake for 15-20 minutes or until risen and golden, stand for 5 minutes, then turn out of moulds (do this up to 2 hours before serving).
Meanwhile, combine cream, remaining milk and vanilla bean and seeds in a saucepan and bring just to the boil over medium heat. Whisk remaining egg yolks and sugar in a bowl, pour over milk mixture, whisk to combine and strain custard mixture into a jug.
Lightly butter four shallow dishes and place a soufflé in the centre of each. Divide custard among dishes, pour over soufflés and dust with icing sugar. Bake for 10 minutes or until golden and custard is just set. Serve with remaining rhubarb and vanilla ice-cream, if desired.