Combine warm water, yeast, and honey in a large bowl. Let stand 5–10 minutes until foamy.
Add molasses, brown sugar, oil, salt, cocoa powder, and instant coffee. Stir to combine, then add both flours and mix until a shaggy dough forms.
Knead 8–10 minutes by hand or 6–8 minutes with a dough hook until smooth and elastic. The dough will be slightly tacky.
Place in a greased bowl, cover, and let rise 1 to 1½ hours until doubled.
Punch down and divide into 3 equal portions. Shape into 8-inch baguette-style loaves.
Dust a parchment-lined baking sheet with cornmeal and place the loaves on top. Cover and rise 30–45 minutes until puffed.
Preheat oven to 350°F (175°C). Brush loaves with water, sprinkle with oats, and score 2–3 shallow diagonal slashes on each.
Bake 25–30 minutes, until the internal temperature reaches 190–200°F.
Cool on a wire rack at least 20 minutes before slicing.