Heat a griddle to 300° F or a nonstick pan to medium heat, just slightly cooler than you’d typically cook pancakes at.
Whisk together all of the dry ingredients until well combined (all ingredients from flour to chia seeds).
In a food processor or blender, puree the berries and spinach in ¼ of milk and the vanilla until smooth. Add enough milk to reach a total volume of 2¼ c after blending.
Add the spinach mixture to the dry ingredients and stir until just combined. Let batter rest for 5 minutes to allow chia seeds to gel.
Pour batter onto the hot griddle to make 8 pancakes. Flip when the bottoms turn a golden brown, cooking a few minutes on each side.