Place a blender on a stable surface. If using the optional greens, add a handful of baby spinach, kale, or other dark leafy greens to the blender first.
Add the 1 very ripe frozen banana (cut into chunks) to the blender.
Add ½ cup cottage cheese or plain Greek yogurt.
Pour in ½ cup unsweetened almond milk or regular dairy milk.
Add one scoop protein powder or collagen powder, if using.
Add about ½ cup ice cubes (use more or less depending on preferred consistency).
Secure the blender lid and blend on high until the mixture is smooth, stopping once or twice to scrape down the sides with a spatula if needed and to check texture.
If the smoothie is too thick, add a little more milk and blend briefly; if it is too thin, add a few more ice cubes and blend until you reach the desired consistency.
Pour the smoothie into a glass, garnish as desired with banana slices, mini chocolate chips, cacao nibs, a dusting of cinnamon or cocoa powder, or whipped cream, and enjoy immediately.