Combine the starter, flours, and water in a large bowl and mix well, until all of the flour is moistened and the dough has come together. Add a splash of water or flour if needed to form a soft, tacky dough.
Cover the dough and let it rest for 20 minutes. The dough will absorb water as it rests and form gluten for easier shaping.
After the dough has rested, add the salt and knead the dough until it’s smooth and springy. The dough will be tacky and a little firm. Once dough has been kneaded, place the dough back in the bowl, cover, and let it rise for 1 hour.
This is how to give the dough a fold: Turn it out onto a floured surface and, using a bowl scraper or bench scraper, fold it like an envelope pulling from the sides. Gently flatten it a bit, and flip it over so the smooth side is up. Return the dough to the bowl, cover, and let it rise for another hour.
Return it back to a floured surface and roll out the dough so it's 1/3 of an inch in thickness using a rolling pin. Sprinkle the beet powder evenly over the dough, keeping about a half inch away from the edges of dough. (See second photo.)Repeat the previous step by folding the dough like an envelope. Turn the dough into a bowl and let rest covered for 30 minutes.
To create the beet layers another fold is needed and this time let it rise for 2 hours.
Once dough has risen, shape the dough into a round boule. Using both hands with a little extra flour holding the dough on a flat floured surface make a circular motion to create a perfectly rough ball. Place the dough seam side down in a Dutch oven or on a baking stone.
Wait 20 minutes and using a lame or sharp knife cut desired design on sourdough.
About 60 minutes before the bread is ready to bake, preheat the oven to 450°F.
Bake for 40 - 45 minutes or until the internal temperature of bread reaches 190°F. The loaf should look golden and have a firm crust. Cool fully on a rack before slicing.
Eat within two days for the best bread. Store in a paper bag at room temperature.
Notes:
For extra crusty bread midway through the bake, add 1 cup of ice cubes to a pan in the oven to create extra steam.