In a large bowl, whisk the bread flour, whole wheat flour, turmeric, coriander, and nigella until combined. In a smaller bowl, mix the water, olive oil, yeast, salt, and sugar until combined. Pour the yeast mixture into the flour mixture, and mix with a wooden spoon until everything is incorporated. The dough will be wet and sticky. 

Grease an extra large bowl with a bit of olive oil. Transfer the dough into the oiled bowl. Make sure the bowl is at least 2 times the size of the dough because it will rise. Cover with plastic wrap and let the dough proof overnight (or at least 8 hours) at room temperature. 

Line a large ovenproof pot or Dutch oven with parchment paper on the bottom and sides. (If needed, you can divide the dough into two and bake smaller loaves in separate pots.) Brush the parchment with olive oil and transfer the proofed dough into the pot. Let the dough rise at room temperature for 30 minutes for one final rise. Place a piece of parchment paper the size of the pot directly on top of the dough, then cover tightly with a lid or aluminum foil.

Preheat the oven to 300F.

Place the covered pot or Dutch oven in the oven and bake for 45–50 minutes. Carefully flip the bread out onto a wire rack, then return it to the pot upside down and bake for an additional 10 minutes. Invert the bread again and serve. Dabo can be stored in an airtight container in the refrigerator for 5–7 days.