Add lukewarm water to a small bowl, just a bit above body temperature. Add the sugar and active dry yeast. Let it sit for 5 minutes so the yeast will activate.
While the yeast activates, add the flour and baking powder into your mixer bowl.
Once the yeast is activated, you should see bubbles on the surface of the mixture. Pour it into the mixer bowl. Mix, until the dry ingredients just absorb the liquid.
Install the dough hook on your mixer. Start at low speed, then gradually increase to speed setting to 6 out of 10. Knead for 10 minutes, until the dough is very smooth. Stop the mixer in the middle and scrape the dough from the sides of the bowl.
Knead on level 6 for another 5 minutes. The dough should be soft, smooth, and easily lift from the bowl without sticking to your hands.
Lightly grease a large bowl with butter or oil. Transfer the dough into the bowl. Cover the bowl with plastic wrap and let it rest in a warm part of your room until the size triples, about 2 hours.