Put all of the ingredients into the blender, in the order listed, and blend on high until thick and smooth. I would start with only 2 Tablespoons of cocoa powder, blend, and then add 1 more for a stronger chocolate taste. You may need to stop and stir/scrape down the sides of the blender a few times. Drizzle glass with 1 teaspoon of chocolate syrup (optional) and enjoy!
If you prefer a less sweet smoothie, you may leave out the honey. Add more peanut butter for a stronger peanut butter taste. Add more milk to make the smoothie thinner, if desired. Add 1 cup of your favorite greens for added nutrition.