In a large bowl, whisk together the all the dough ingredients except for the vegan butter. Knead until smooth.

Add vegan butter continue kneading until the dough is very elastic -- about 20 minutes in a machine.

Shape into a ball and place in a bowl. Cover and let rise for 1 hour, or until doubled in volume.

While the dough is rising, make the filling: In a bowl, mash the beans into a smooth paste (or use a food processor). Add some sweetener to your desired level of sweeteness, and add some water if the mixture is too dry. Divide the filling mixture into 8 equal portions.

Once the dough has risen, punch it down and divide it into 8 pieces. Shape into balls and let rest for 10 minutes.

Then, roll each piece out into a flat circle, and place a piece of the bean paste in the center. Pull all sides of the dough around the filling, then pinch the seams together.

Gently roll each dough ball on a flat surface with the seams down, and place on a lined baking tray. Let rest for 30 minutes.

Preheat your oven to 375F/190C. For a "flatter" shape, place a baking tray on top of the buns, then bake for 25 minutes or until golden brown on top. Let cool and enjoy!