Make sure your banana is frozen solid. If you have not frozen it yet, peel and slice it and lay the slices flat on a small plate or sheet of parchment. Freeze for at least two hours before using. This is the step that gives the smoothie a thick, almost creamy texture without using ice.

Add the cold water to the blender first. This helps the blades get moving without strain and prevents the spinach from getting stuck under the blade.

Add the baby spinach on top of the water. Then add the chopped apple and cucumber. Add the frozen banana slices last, on top of everything. Drizzle the lemon juice over the top.

Put the lid on securely and blend on high speed for a full 60 to 90 seconds. Do not stop at 30 seconds. You need the full time to break down the spinach completely so the texture is smooth and not grainy. If the blender stalls, turn it off, stir with a long spoon, and blend again.

Take the lid off and check the texture. It should be thick and pourable, not chunky. If it looks too thick for your taste, add another splash of cold water, replace the lid, and blend for 10 more seconds. Pour into a large glass and drink immediately for the best flavor and color.