Prep: Preheat your oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners or grease well.
Blend Wet Ingredients: In a blender, combine the eggs, banana, carrots, spinach, maple syrup, oil, vinegar, and vanilla. Blend until the mixture is completely smooth and bright green.
Incorporate Dry Ingredients: Add the flour, baking powder, baking soda, salt, cocoa powder, and cinnamon to the blender. Pulse or process until just combined. Note: If using a standard blender, pour wet mix into a bowl and stir dry ingredients in by hand to avoid overtaxing the motor.
Fold: Gently fold in the chocolate chips with a spatula.
Bake: Portion the batter into the muffin tin. Sprinkle a few extra chocolate chips on top if you’re feeling fancy. Bake for 20–22 minutes.
Test: Muffins are done when a toothpick comes out clean or the internal temperature reaches 200°F.
Cool: Let them sit in the pan for 5 minutes before moving to a wire rack. Cool completely before storing.