Lately I have several times made a variation of Sourdough Baguettes in which I have incorporated some whole grain flour and have formed the dough into a single boule to simplify the process. Here is the basic recipe and process. The last time I did this, I used KFA 9-grain blend as the whole grain flour. I have also been using a ceramic bowl sold by KFA in which to bake the boule.
Poolish
100 g. sourdough starter
75 g. all-purpose flour
75 g. water
Dough
250 g. Poolish
150 g. whole grain flour
150 g. bread flour
1 tsp. salt
¼ tsp. yeast
140 ml. tepid water
The night before, mix together in a bowl the sourdough starter, flour and water for the polish. Cover and let it ferment on the counter over night. (This is a good time to refresh the sourdough starter with equal weights of flour and water.)
The next day, about 5 hours before you want the bread to be done, mix together in a large bowl the polish and all the dough ingredients. Mix first with a dough wisk and then with a hand moistened in a small bowl of water. Allow to rest covered for 10 minutes. Three more times, knead the dough with a moist hand, resting 10 minutes between kneadings. After these 4 kneadings, the dough should be a smooth ball. Cover and allow to rise until doubled, about 2 hours.
Prepare the baking dish by lightly coating it with oil and sprinkling cornmeal on the bottom. Punch down the dough and form it into a boule shape with oiled hands. Put it in the baking dish and cover with plastic wrap. Allow it to rise for another 2 hours. About 30 minutes before baking, preheat the oven to 475 degrees, including a baking steel and a cast iron skillet in the oven. Slash a hashtag pattern in the top of the boule to help it expand while baking. Put the boule in the oven on top of the baking steel and put about a cup of boiling water in the cast iron skillet to form steam. Bake for about 20-22 minutes until the crust is nicely browned and the internal temperature of the loaf is 190 degrees. (I used a wired thermometer usually used for meat.) Allow to cool in the baking dish on a rack for 5 minutes and then remove it from the baking dish and allow to fully cool on the rack.