Brew and cool the coffee. Make your coffee ahead of time and let it cool to room temperature or chill it in the fridge. Warm coffee can melt the banana and thin out the texture.
Load the blender. Add the cooled coffee, milk, frozen banana, protein powder, cocoa powder, nut butter (or seeds), vanilla, and a pinch of salt. If you like it thicker, add a few ice cubes.
Blend until completely smooth. Start on low to break up the frozen banana, then increase to high for 20–30 seconds.
The texture should be creamy and uniform with no grainy bits.
Taste and adjust. If you want it sweeter, add a touch of maple syrup or honey. For more coffee flavor, splash in a little extra cooled coffee and blend again.
Serve immediately. Pour into a chilled glass or an insulated cup if you’re on the go. Top with a light sprinkle of cocoa powder or cacao nibs for a café finish.