In a bowl, combine lukewarm plant-based milk (should not exceed 105 degrees F/40 degrees C), yeast, and 1/2 tbsp sugar. Let sit for 10 minutes to proof the yeast. If it get's frothy your yeast is fine. If not, your yeast is most likely old and cannot be used.
In a big bowl, combine all dry "dough ingredients" (flour, psyllium husk powder, sugar) and mix with a whisk. Once the yeast has proofed add the yeast mixture.
Add the soft vegan butter as well and knead the dough with your hands. It might appear too wet at first (depends on which flour mixture you used) but the dough consistency will be fine after a few minutes and should look like this:
If the dough is too dry though, add a little bit more plant-based milk. If it appears too wet, add more flour. Put cling foil on top of the bowl (you don't want the dough to dry out) and let it rise for about 30-60 minutes. After that, it should have risen quite a bit:
Divide the dough into 8-9 parts (90-100 grams each) and fill each dough ball with plum jam (or jam/jelly of choice).
Seal the filling with more dough and roll the dumpling between your hands to form a ball. Put all dough balls on a floured plate and let them rise again for about 20 minutes (preferably covered with cling foil).
Once the time is up, heat a pan over medium heat, add oil, water, and salt and bring to a boil. Add about 4 dough balls (if you have a big pan you can add more) and put a lid on top of the pan/skillet). Steam for about 25 minutes and do NOT lift the lid during the first 15 to 20 minutes (otherwise the dumplings might collapse).
You will hear when the water has evaporated and the crust begins to form. Enjoy warm with vanilla sauce and poppy seed sugar.