Japanese steamed buns with olive oil

Ingredients for the stuffing:

100 gr finely chopped onion
100 gr finely chopped cabbage
15 gr sesame seed oil (if you don't have it evo oil) to sauté the vegetables
15 gr shoyu or tamari
salt to taste
grated ginger to taste.

Ingredients for the rolls:

125 gr of semi-wheat flour
65 gr lukewarm water
5 gr sugar to help leaven
3 gr of brewer's yeast powder (or 9 gr of fresh one)
olive oil or sesame seed oil to taste
salt to taste
Potato starch for kneading

Preparation

Finely chop vegetables and saute with olive oil and salt. Add ginger and soy sauce. Leave in the refrigerator to rest.

For the dough: mix flour, yeast, water, salt and a drop of olive oil, sugar and create a ball. Cover it and let it rise for an hour. Dust a work surface with potato starch and divide the dough into 4 small balls. Crush each ball with your fingers and roll it out with a rolling pin. Create a flour disk and fill it with some of the filling. Close the disk, creating a pointed bundle. Do the same thing with the remaining rolls. Now let rise for another 30 minutes. Prepare the steaming pan and place the buns on the baking paper. Steam for about 15 minutes on medium low heat.

Source: https://www.officinadellafelicita.org/post/panini-giapponesi-al-vapore