Whisk together the cold water and cornmeal. Let sit for 5 minutes then add the boiling water and whisk together. Let stand 10 minutes. Sprinkle yeast over the 1/2 c water with 1 tsp honey or molasses in a separate bowl. Let stand 5 minutes. Add buttermilk powder(I haven't been able to find this so I just used milk powder and added a tbsp of vinegar), remaining honey or molasses(I used about 1 tbsp honey and the rest regular baking molasses), wheat bran, and whole wheat flour to the cornmeal and water along with the softened yeast. Mix well and set aside, covered, for one hour. It will double.
Sprinkle oil, salt, and sesame seeds over sponge and mix in. Add bread flour 1/2 c at a time till a soft dough forms. Turn out and knead till smooth, about 2-4 minutes. Don't add too much flour as the dough should be sticky. I found it to be very sticky, but the end result is very good, so don't aim for dough that isn't sticky. It will be considerable less sticky after it rises. Coat with oil and leave dough 2 1/2 - 3 hours till doubled. Turn out and divide into 4. Roll into tight round balls(you may need to use a little flour or else it will stick to your surface and your hands) and place 4" apart on parchment lined sheets sprinkled with cornmeal. Sprinkle the tops of the loaves with wheat bran, the cover with a towel and let rise about 45 minutes.
Preheat your oven to 400 degrees. If you can, gently tuck the sides of the loaves underneath itself to make higher loaves, but be very careful not to deflate them. I usually place a dish of water in the bottom of the oven when I turn it on to make it steamy inside. This will help the bread spring up in the first few minutes of baking. Put loaves in the oven and bake 10 minutes then turn the oven down to 350 degrees and bake for 25-30 minutes till done. You may need to loosely cover the loaves in a piece of tin foil to prevent them from over browning near the end of baking.