It’s hard to write a recipe for green smoothies, every one I make is different. The basic formula I’ve read—in Twelve Steps to Raw Foods and Green for Life by Victoria Boutenko—suggests starting with 60% fruit and 40% greens, then gradually increasing the percentage of greens until you are using 60% greens and 40% fruit. I often just go with 50/50.
Here is a basic smoothie:
One banana, peeled
Frozen organic blueberries (1 cup)
One to two cups greens: spinach (stems and all) or kale (lactinato/dino kale is best). If using kale, remove the leave from the center stem before adding to the blender.
Two to three cups water, depending how thick you want your smoothie.
Blend and serve cold.
It is possible to use other greens—lettuce, chard, dandelion, or turnip/radish greens, though some people don’t like the flavor of these. The chard can sometimes taste muddy, while turnip and radish greens can be too assertive, peppery. Make sure to add enough fruit to balance this out.
You can add almost any other fruit: all kinds of berries (cranberries even, though not too much or it turns very tart), cherries, peaches, mango, apple, pear, melon, etc.
In the summer I also add herbs: basil or mint. I tried cilantro but do not recommend it.
Experiment and play, you’ll find some combinations you like. If the flavors start tasting too “grassy” for you, just add more fruit.
Green smoothies will last a day or so, if kept cold. Though it’s probably best to drink them sooner rather than later.