Make flax egg: Mix ground flaxseed with water and let sit 5 minutes to thicken.
Blend wet ingredients: In a food processor or blender, add fresh spinach, banana, milk, vanilla, and melted coconut oil. Blend until completely smooth.
Mix dry ingredients: In a large bowl, whisk together flour, baking powder, and salt.
Combine batter: Pour the green mixture and flax egg into the dry ingredients. Stir just until combined. (Add 1–2 tbsp flour if you want a thicker batter.)
Heat skillet: Warm a large nonstick skillet over medium heat and lightly grease with coconut oil.
Cook pancakes: Scoop batter onto the skillet and cook 2–3 minutes, until bubbles form and edges look set. Flip and cook 1–2 minutes more, until golden brown and cooked through.
Serve: Enjoy warm with maple syrup, fruit, or peanut butter.