I would think about scaling back, or even eliminating the baking powder, and maybe bumping up the baking soda a little. It may be heresy, at least Marcy Goldman says it is, but I find myself taking out the baking powder when a cake has a lot of honey, brown sugar, coffee, cocoa, or any other acidic ingredient. I was making honey cakes that absolutely frothed until I removed the baking powder. And the same with multiple sheet pans of devils food cake. The baking soda alone is enough to leaven. And it will turn the cocoa darker. It's not the same chemical normally used to dutch cocoa.