In a standing mixer, add warm water, oil, yeast, and sugar. Allow to sit for 1 minute, then add in the flour, baking powder, and salt. Mix until dough comes together, adding more flour until dough doesn’t stick to the sides of the bowl. Mix on medium for ten minutes. Turn out dough and hand-knead into a ball. Cover and allow dough to rise for one to two hours. When dough has doubled, punch it down and form into a log. Cut log into 12 portions. Knead each portion into a ball. With rolling pin, roll out each ball and brush with oil; fold each in half and roll each once more to seal. Place buns in a steamer basket with ample water. Turn on heat to start water boiling; once water starts to boil, set timer for five minutes. Turn off heat and allow buns to sit for another two minutes.
Fill each bun with equal portions of shredded meat, carrots, cabbage, and cucumbers. Top with gochujang and serve.