Add the ice, milk, protein powder, banana, Greek yogurt, cocoa powder, vanilla extract and salt to a high-powered blender.
Blend until thick, smooth, and creamy, using the tamper if your blender has one. Stop and scrape down the sides as needed. You want the mixture to be thick, but if it’s too thick to blend, add more milk, 1 tablespoon at a time, until it reaches your desired consistency.
Taste and add a little more cocoa powder if you'd like a richer chocolate flavor.
Pour into a glass and enjoy immediately.