Place all ingredients in a high-speed blender. Puree until smooth. Serve.: Right away you will notice the arrangement matters, the frozen banana and cashews should be closest to the blades so they break down quickly. You may hear a heavier thud at the start as the frozen fruit hits the blades, which is normal. The spinach will look bulky but collapses quickly as air and liquid are incorporated. If your blender struggles, stop and scrape down the sides, then add a splash more water to help movement. Avoid overfilling the jar as that can prevent proper circulation.
Puree until smooth: As the blender runs the mixture will transform from chunky to velvety, and you will see a uniform pale green color appear. Listen for the change from loud churning to a steadier hum, that signals full emulsification. The aroma should shift from raw leafy notes to a sweet, minty scent. If you still detect small bits of cashew or fibrous streaks of spinach , pulse a few more times rather than running continuously, to avoid warming the mixture. One mistake is blending too briefly, leaving gritty textures behind.
Serve: Pour immediately into a chilled glass so the frothy top and cool temperature shine. The surface will have a pale green foam, and the body should cling slightly to the sides of the glass as you sip. I like to garnish with one additional mint leaf if I have it, purely for the aromatic lift. Drinking right away preserves the best texture and temperature, waiting too long will thin the drink as the ice melts.
