Preheat oven to 200˚C (400˚F) and grease a square baking pan (8-in x 8-in). In a large mixing bowl, sift flour and baking powder. In another bowl, beat the butter and sugar into a cream. Add the aquafaba, the milk and the vanilla extract. Mix until you get a smooth consistency. Add the dry ingredients (flour and baking powder) and mix just enough to combine. Whisk the sauce ingredients directly in the bottom of the baking pan until well-combined. Using a spoon, place dollops of the dough on top of the sauce. Place in the oven and bake for approximately 35 minutes. Take out, let cool slightly and enjoy. Bon appétit!