Prep and preheat: Heat the oven to 375°F (190°C). Line a 12-cup muffin tin with liners or lightly grease.
Make the flax egg: Stir ground flaxseed with water in a small bowl. Let it thicken for 5 minutes.
Grate the zucchini: Finely shred and gently blot with a clean towel to remove excess surface moisture.
Don’t squeeze it dry.
Mix the wet: In a large bowl, whisk non-dairy milk, oil, maple syrup, vanilla, and the flax mixture until smooth. Fold in the zucchini.
Add the dry: Add flour, cocoa, sugar, baking powder, baking soda, salt, and cinnamon directly to the bowl. Stir until just combined.
The batter will be thick; don’t overmix.
Stir in chocolate: Fold in chocolate chips. Divide batter evenly among muffin cups. Sprinkle a few extra chips on top for a bakery look.
Bake: Bake 16–19 minutes, until the tops spring back and a toothpick comes out with a few moist crumbs (melted chocolate is fine).
Cool: Let muffins rest in the pan 5 minutes, then move to a rack to cool completely.
Make the drizzle: Whisk tahini, maple, a pinch of salt, and just enough milk to reach a drizzleable consistency.
Adjust sweetness to taste.
Finish: Drizzle over cooled muffins. Let set for 10 minutes, then enjoy.