Mix the dough: In the bowl of a stand mixer with a dough hook, combine the flours, kosher salt, and yeast. Stir lightly with the dough hook to combine. Add the water and Greek yogurt and stir again until just combined. (Note: You need a stand mixer for this recipe as kneading by hand would be too sticky.)
Proof the dough: Place bowl and dough hook on stand mixer and knead for 8 minutes on low speed. After mixing, transfer the dough to a small bowl. Cover and allow to rise in a warm place (we use an 80° proofing oven) until doubled in size — 1.5 to 2.5 hours.
Preheat the Dutch oven: When the dough has risen, place a Dutch oven in the oven and preheat to 475°F. Prepare a piece of parchment paper about 8 inches wide by 12 inches long.
Shape the dough (watch the video instructions!): Scrape the dough onto a lightly floured counter; the dough should be formed into a gently rounded shape. Rub just enough flour onto the top of the dough so that it isn’t tacky. Use the bench scraper to flip the dough so that the floured side is down. Gently stretch the dough into a rectangle. Moving quickly, fold the top third of the dough down, and the bottom third up to create a packet. Rotate the dough 90 degrees and gently roll it into a log shape. Be careful to not press the dough or deflate it. Use your hands to gently pull the dough tight and pinch off the seams at the end of the dough. Carefully transfer the dough to the parchment paper and allow to rest uncovered for 30 minutes.
Bake the bread: After the dough has rested, use a lame or sharp knife to cut a shallow slit at angle across the top of the dough. As quickly as possible, using a hot pad remove the lid from the Dutch oven and carefully place the parchment paper with dough into the Dutch oven. Cover it and set the timer for 17 minutes.
Reduce the oven temp and continue baking: After 17 minutes, reduce the oven temperature to 400°F. With a hot pad remove the Dutch oven, carefully take out the bread. and set the bread directly onto the oven rack. Bake for an additional 23 minutes.
Cool the bread: Remove the bread from the oven and allow it to cool on a cooling rack for at least 45 minutes. After cooling, the bread is ready to eat. Store the bread wrapped in cloth or in a bread bag on the counter for up to 2 days, or freeze it wrapped in foil in a plastic bag for several months.