Preheat oven to 350°F and line a 12-cup muffin pan with liners (or use a silicone muffin pan).
Mix dry ingredients: In a large bowl, whisk together flour, cocoa powder, baking powder, baking soda, and salt. Set aside.
Blend wet ingredients: In a high-speed blender, combine carrots, zucchini, spinach, Greek yogurt, honey, oil, eggs, and vanilla. Blend until completely smooth.
Combine: Pour blended mixture into the dry ingredients. Stir gently until just combined — do not overmix.
Add chocolate chips: Fold in mini chocolate chips.
Fill muffin pan: Scoop batter evenly into the muffin cups. Sprinkle extra chocolate chips on top.
Bake for 18–24 minutes, checking around the 18-minute mark. Muffins are done when a toothpick comes out clean.
Cool on a wire rack before devouring (if your kids will wait that long).
