First, brew your coffee and let it cool down completely. If you're in a hurry, you can put it in the freezer for 10 minutes or use coffee you made earlier.
While the coffee is cooling, peel your banana and gather all your other ingredients. This is also a good time to measure out your milk, cocoa powder, and honey if you're using it.
Once your coffee is cool, add a splash of milk and the cocoa powder to your blender. Blend these together first - this helps prevent cocoa powder clumps in your smoothie.
Now add the rest of your ingredients to the blender: the banana, cooled coffee, remaining milk, vanilla extract, and ice cubes. If you're using honey for extra sweetness, add it now.
Blend everything together until it's smooth and creamy. This usually takes about 60 seconds. If you see any chunks, keep blending. Stop and scrape down the sides of the blender if you need to.
Pour your smoothie into a tall glass. You can drink it just like this, or make it extra special by adding some toppings.
If you want to add toppings, add a swirl of whipped cream on top, drizzle with chocolate syrup, and sprinkle a little cocoa powder. A metal straw makes it look nice and helps the environment too!
Drink your smoothie right away while it's fresh and cold. If you have any leftover, you can keep it in the fridge for up to 24 hours - just give it a good stir before drinking.