Combine all ingredients in a blender. Add about ¾ to 1 cup water.
Blend until smooth, about 1 to 2 minutes, and enjoy!
Notes
This smoothie is best enjoyed right away, but you can keep leftovers in a sealed jar or container in the fridge if desired. They should last 1 to 2 days.
To freeze individual portions, pour into freezer-safe jars or containers, leaving an inch of headspace to allow for expansion. Seal tightly and freeze for up to a month. Transfer from the freezer to the fridge to thaw overnight or for at least several hours. Shake or stir well before enjoying. Freezing then thawing may cause texture changes.
Using a high-powered blender and blending for at least a minute will yield the creamiest texture and break down tough ingredients. A blender without as much power may lead to flecks of spinach in the final product, but the smoothie will still taste delicious.