Persian Barbari Bread (No Knead, Whole Wheat)

Mix the Dough (Night Before)
1 Activate the yeast:
In a large bowl, pour in the warm water (about 125°F for instant yeast). Add the sugar and stir to dissolve. Sprinkle the yeast over the surface and let sit for about [timer minutes=5]5 minutes[/timer], until lightly foamy.
2 Mix the dough:
Add the bread flour, whole wheat flour, and salt. Using a Danish dough whisk or sturdy spoon, mix until fully hydrated and shaggy. The dough should be soft and slightly sticky. Tip: You should be able to stir the dough easily with a dough whisk or wooden spoon. If it feels tight or difficult to mix, the dough is too dry; add a little water as needed.
3 Drizzle the olive oil over the surface of the dough (do not mix it in). Cover the bowl and refrigerate for 12–16 hours.
Strengthen the Dough (Next Day)
5 About 2 hours before shaping, remove the dough from the refrigerator.
6 Perform one gentle stretch-and-fold directly in the bowl: Lift one side of the dough, stretch it upward, and fold it over the center. Rotate the bowl and repeat until all sides are folded.
7 Let the dough rest 30 minutes. If the dough still tears easily, perform another stretch and fold. The dough should feel smoother and slightly elastic but remain soft and airy.
8 Divide the Dough: Turn the dough onto a lightly floured surface. Divide into 3 portions for medium loaves or 2 portions for larger traditional loaves. Gently shape each portion into a loose oval without pressing out too much air. Let rest [timer minutes=30]30 minutes[/timer].
9 Prepare the Roomal: In a small saucepan, whisk together the flour, water, sugar, and baking soda. Cook over low heat, stirring constantly, until the mixture thickens into a smooth glossy paste. Remove from heat and let cool slightly. Roomal helps create the distinct golden crust and traditional appearance of Barbari bread.
Shape the Barbari Loaves
11 Using lightly floured fingertips, dimple the dough balls and gently stretch each dough portion into a long oval about 12 inches long and 6 inches wide. Let rest [timer minutes=15]15-20 minutes[/timer] to relax and rise slightly.
13 Brush the surface generously with roomal. Using your fingertips, press deep parallel grooves lengthwise across the dough (or use the back of a butter knife). These grooves prevent the bread from puffing like pita and give Barbari its traditional look. 
26 Sprinkle generously with sesame and nigella seeds.
15 Stretch gently to about 16 × 8 inches and transfer the dough to the back of a baking sheet dusted with wheat bran or coarse cornmeal. Tip: The shaped dough should be at least ½ inch thick.
Bake
17 Preheat the oven to 525–550°F (275–290°C). Bake for [timer minutes=8]8–10 minutes[/timer], until the bread is deeply golden with crisp edges. Optional: Broil for 30–60 seconds for additional browning, if needed. Watch carefully to prevent burning.
Cool
21 Transfer the baked bread to a wire rack or wooden board. Allow to cool slightly before serving. Barbari bread is best enjoyed warm, when the crust is crisp and the interior tender.