Bloom the yeast in the warm water for 10 minutes, then mix all the remaining dough ingredients together in a bowl. Knead on a floured surface for 5 minutes, then cover and proof for 1 hour or until approximately doubled in size.
Make the filling while the dough is proofing. Heat the butter in a large pan and cook the onion over medium heat until soft. Add the remaining ingredients *(see below) and simmer until the liquid is all gone (absorbed/cooked off). Turn off the heat and let cool to room temperature.*If using vegetarian protein options, add to mix while cooking to promote hydration of the protein. If using a ground meat option, do not cook the meat at this stage. Add the uncooked meat to the mix after cooling. The meat will cook when baked. After your dough has finished proofing, punch it down and pinch off balls approximately 2 inches in diameter. The dough should yield approximately 12 balls. If not working quickly or immediately, cover dough with damp towel or plastic to prevent skin from drying out.
Take one ball and flatten with hands or a rolling pin. Flattened ball should be approximately 5 inches across. Flatten the edges more than the center, so when you seal it, the bottom of the roll isn't too much thicker than the top.
Use about an ice cream scoops worth of filling and place in the center of the flattened dough. Wrap the dough around the filling and pinch to seal. Pay attention to minimize the amount of dough you end up pinching into the center. If a mound is formed inside the roll, it will rise while baking and cause your filling to burst through the thinned out top.
Place roll aside and repeat with remaining dough balls.
Add baking soda to the 9 C of water and heat until boiling. Dunk prepared rolls in this mixture for 15-30 seconds. Longer may result in your rolls tasting a bit metallic.
Bake rolls for 15 min at 375 degrees F. Pull out and brush liberally with butter. Add salt or seasoning to the tops. Bake for an additional 5-10 minutes or until dark brown. If using meat, ensure your proteins food safe temperature has been reached by checking the internal temperature of a roll.