In a medium bowl add the warm water, yeast, and sugar. Give a few stirs. Set aside for 20-30 minutes or until bubbly.
Grind the gluten free oats, cornstarch and 1 tablespoon caraway seed in a Vitamix or food processor. Process until the oats are a fine flour. The caraway seed may not process to flour, but will be smaller seed pieces.
In a large bowl add the tapioca flour, Ryze flour, Bob’s 1 to 1 flour, ½ teaspoon caraway seed, salt, cocoa powder, ground espresso, coriander, and oats/caraway seed processed mixture. Stir to combine.
Add the yeast mixture to the bowl, then the sourdough starter, molasses, warmed milk, apple cider vinegar, garlic, and olive oil. Mix with a rubber spatula to thoroughly combine. Add in enough Ryze flour and Bob’s 1 to 1 flour to make a stiff dough.
Turn out onto a gluten free floured board and knead for 5 to 7 minutes adding in additional Ryze flour or Bob’s 1 to 1 flour to attain a smooth, stiff but still pliable dough. Cover with a towel and let rest for 20-30 minutes.
Form into a ball, smoothing the top by folding the sides of the ball to the underside.
Set in a floured sourdough banneton basket or a large bowl lined with a damp and floured towel. Place a dry towel over the top and let rise in a warm place for 2-4 hours, until approximately 1 ½ times the size and when indented with your finger, it gently springs back.
Preheat the oven to 450 degrees F. Preheat your 4 qt. or 5 qt. Dutch oven while the oven is preheating.
Place a 15” square sheet of parchment over the top of the bread dough, and cover with a cutting board. Holding the cutting board and the basket or bowl with bread between both your hands, gently flip over and set the cutting board down on the counter. Remove the basket or bowl.
Remove the basket or bowl. Cut decorative slits into the top of the bread round.
Remove the preheated Dutch oven from the oven. Holding the edges of the parchment gently lift the bread round into the Dutch oven.
Set the lid on the Dutch oven. Bake the bread for 25 minutes covered, then uncover and lower the oven temperature to 375 degrees F. Bake for 20-30 more minutes until the bread is golden on top and the internal temperature of the bread is 207 degrees. Remove to a wire rack and cool for several hours before slicing.