For the easiest version, squeeze the lemons and stir everything together. If you are having a hard time getting the spirulina evenly mixed, a quick blending with an immersion blender works well. You can also start off making a paste with the juice of one lemon and the spirulina, stirring until evenly mixed and then whisk together all the remaining lemon juice and extracts before adding the rest of the ingredients.

For the more floral lemon flavor version, slice the lemons thin and then combine all ingredients except water in a large bowl and mash with a wooden spoon until the lemons have released all their juice. Strain the lemon and pulp out using a fine mesh strainer, pressing on the solids with the wooden spoon to extract as much liquid as possible. Discard the solids and add the cold water to the strained liquid. Serve with ice.