For dry yeast: In a large electric mixing bowl, combine the flour with the dry yeast. Allow the yeast to activate for 10 minutes. Then, add the milk and follow the instructions below as the third step.
For fresh yeast: Crumble the yeast into a large electric mixing bowl, pour finger warm milk (98 ℉ / 37 ℃) over and allow the yeast to dissolve.
Add the flour, sugar, freshly grounded cardemum seeds and thanzong starter and mix on low speed for 10 minutes.
Whisk an egg and to the dough along with the salt, combine for another 5 minutes on low speed.
Cube the butter and feed the dough one piece at the time, allowing the dough to fully incorporate the butter in between.
Increase the speed to a medium and mix for 20-30 minutes. The dough should be elastic and shiny when ready. Do a gluten test by grabbing a small piece of the dough and stretching it out thin enough to see the light from the window come through the dough. If the dough breaks, then keep mixing for another 10 minutes and redo the test.
Once the dough is shiny and elastic, take it out on a clean surface and roll into 15 small balls about 80 g each. Roll the buns by cupping your hands over the dough and moving your hands in circular motion against the surface. The dough can be slightly sticky so a little flour on the surface can help, but not necessary.
Place the buns on baking trays with parchment paper, with at least 2 inches (5 cm) in between each bun as they will rise double their size. Cover with a clean kitchen towel and allow to proof for 2 hours. I like to place mine the oven with the oven light on but no heat. If you live in a warmer climate, this might not be necessary.