Step 1

Peel 1 large banana, then tear or slice into 1-inch pieces. Arrange the pieces on a parchment-lined baking sheet, and freeze until solid (at least 2 hours).

Step 2

Add 1 cup unsweetened vanilla or plain almond milk or whole milk, 2 tablespoons creamy peanut butter, any of the optional ingredients (if desired), and the frozen banana pieces to a blender. Blend on high speed until very smooth, stopping to scrape down the sides of the blender as needed, 30 to 60 seconds. Pour into a tall glass and serve immediately.