Vinegar Pudding (asynpoeding)

Preheat oven to 180°C. Grease a 2 L casserole dish or ovenproof dish with butter. Combine 110 g of the sugar with 125 ml water in a saucepan over medium heat. Simmer for 8 minutes or until reduced by one-third. Stir in vinegar and set aside.
Using an electric mixer, beat butter and remaining 220 g sugar until pale. Add jam and beat until well combined. Add vanilla then add egg yolks, one at a time, beating well after each addition. Fold in flour. Whisk remaining egg whites in a clean bowl to stiff peaks, then fold into the batter in 2 batches.
Transfer mixture to prepared dish and pour vinegar sugar syrup over the top. Place dish in a deep roasting pan and pour in enough boiling water to come halfway up the sides of the pan. Bake for 40 minutes or until cooked through, covering with foil halfway through cooking if pudding is browning too quickly.
Meanwhile, to make poached apricots, place the apricots, caster sugar, vinegar, vanilla beans and seeds, and 375ml water, in a saucepan over medium heat. Stir to dissolve sugar, then simmer for 12 minutes or until syrupy. Remove from heat and set aside to cool. Dust pudding with icing sugar, drizzle with thickened cream and serve with poached apricots.