I'm glad you bumped this thread - I just bought some chocolate protein powder that doesn't taste too great as a shake, so I was going to look for a muffin recipe.

I accidentally overbaked the first batch so they were pretty dry, but the second ones were a lot better.

I omitted the maple extract and substituted it with almond extract. Almond extract doesn't smell nutty; it smells... cakey. Buy some and take a whiff. It made these muffins taste really fudgy.

I also whipped up a bit of cream cheese icing for them. Yum!