Preheat the oven to 350. Line 12 muffin cups with cupcake liners or lightly mist the muffin tin with cooking spray.
In a large bowl, combine the flour, sugar, baking soda, cinnamon and salt and stir until mixed.
In a medium bowl, combine the egg, applesauce, milk, lemon juice and vanilla. Stir until mixed.
Pour the bowl of wet ingredients into the bowl of dry ingredients and stir until combined, forming a moist batter. Fold in the zucchini and chocolate chips.
Spoon the batter evenly into the liners. Bake for 20-25 minutes. Cool on a wire rack.