In a large mixing bowl, stir together warm water, brown sugar, and instant yeast. Let sit for 5–10 minutes until foamy.
In a separate bowl, whisk together bread flour, whole wheat flour, cocoa powder, and salt.
Once the yeast is activated, add melted butter, molasses, and honey to the yeast mixture. Stir to combine.
Add about ⅔ of the flour mixture into the wet ingredients and mix until a soft dough forms.
Add the remaining flour mixture and knead by hand for 5–7 minutes (or in a stand mixer with a dough hook for 3–5 minutes) until smooth and elastic.
Place the dough in a greased bowl and cover. Let rise for 2 hours, until doubled in size.
Divide dough into 4 equal pieces. Shape each into a long, skinny loaf and place them on a parchment-lined baking sheet.
Cover again and let rise for another 45 minutes to 1 hour.
Preheat oven to 350°F. Lightly brush or spray the tops with water (optional) and sprinkle with rolled oats.
Bake for 25–30 minutes, until the loaves sound hollow when tapped.
Cool slightly before slicing. Serve warm with butter.
