Warm the milk in the microwave until it is just warm to the touch (100°-110°).
Add the warm milk, brown sugar, and yeast to a large mixing bowl and stir gently. Let the mixture sit for about 5-10 minutes until the yeast is activated and the mixture is frothy.
Add the molasses, honey, butter, wheat flour, all-purpose flour, and cocoa powder. Use a wooden spoon to mix everything until well combined. You can use a stand mixer if you'd like, but you definitely don't want to mix very long. I have had better results with this bread when I've mixed it by hand!
Place the dough into an oiled bowl and cover with a clean dish towel.
Set aside to rise for about 1 hour. Once the dough has doubled in size, knead it for about 3-5 minutes on a lightly floured surface until smooth.
Separate the dough into 3 even portions.
Roll each portion into an 8-inch long loaf and place on a parchment-lined baking sheet. Sprinkle the tops with the oats.
Gently cover with a clean dish towel and set aside to rise for about 30-40 minutes. Once the loaves have risen, place them in an oven that has been preheated to 375°.
Bake for about 20-25 minutes. Remove from the oven and set aside to cool slightly before slicing.
Serve warm with whipped butter.