Preheat the oven to 180ºC and grease a small (20cm square) oven-proof glass dish.
In a medium bowl, whisk the aquafaba and sugar together.
Mix in the apricot jam, then add the melted vegan butter, and the vinegar.
Mix in the plant milk.
Add the flour (don't mix yet). Add the bicarb and salt, then mix everything together.
Beat well, then pour into the oven dish.
Bake for 30-40 minutes, until well risen and a cake tester comes out clean.
Meanwhile, in a small pot over medium heat, melt together all the ingredients for the sauce, and stir well.
Pour the sauce over the pudding as soon as it comes out of the oven.
Leave to stand until the sauce is fully absorbed, then serve with vegan ice cream and/or custard.