Add the spinach and all liquid ingredients to a blender and blend thoroughly, until smooth with little or no flecks of spinach visible.
In a separate mixing bowl, combine the remaining (dry) ingredients, and stir to combine.
Pour blended ingredients into the mixing bowl and stir until the batter is just combined. A lump or two is OK-- don't overmix.
Heat a skillet over medium-low heat and melt a bit of butter in the bottom. Add small scoops of batter to the skillet (2-3 tablespoons of batter per pancake works well) and cook 2 minutes.
Flip the pancakes and cook a minute or two longer until the pancakes are fluffy and cooked through.
Repeat until all the batter is used up.
Notes
to get the GREENEST pancakes, use white whole wheat flour and cook at a lower temperature to prevent browning on the ouside.