Peel and grate the ginger, scoop out the avocado flesh, and chop the spinach leaves.
Using a blender, mix all of the ingredients (except chia seeds and stevia) for a minute to obtain a smooth and uniform mixture. Optionally, pour some water and lime juice into the blender to produce the desired thickness.
Include some ice cubes and the sweetener into the mix just to flavor it up. Transfer to a glass and garnish with a teaspoon of chia seeds on top. Give a stir and serve immediately.