Place lettuce, banana, and water in Vitamix. Start with low speed (#1). Lightly tamper the greens toward the blades. It may help to tamper at the corners of the container before swirling the tamper throughout the container. Increase the speed to about #6 until the greens and banana have blended. Add additional water if necessary. If too much water is used, add ice cubes to reach desired icy consistency. Increase the speed to #10. Then turn the blender to high and super blend for 30 more seconds or until the mixture is smooth. Turn machine off and serve immediately.
This is the backbone to a lot of smoothies. The smoothie may be made sweeter by adding more fruit or mint. It may be made more savory by adding ingredients like cilantro or basil.
Source of recipe: Basic recipe.