Preheat oven to 350F and line 10 muffin tin cups with muffin liners.
Grate zucchini on a cheese grater. Use a tea towel to squeeze out the excess moisture from the zucchini. Really squeeze it! Pour grated zucchini into a large mixing bowl with the egg, sugar, vegetable oil and vanilla extract.
In a separate bowl combine the flour, cocoa powder, baking soda and salt. Fold dry ingredients into wet with a rubber spatula. The batter will be thicker than a standard muffin batter.
Mix in the chocolate chips and place ¼ cup of batter in each of 10 muffin cups. Top with more chocolate chips.
Bake at 350F for 22-24 minutes. Cool completely and enjoy.
Notes
To make gluten free you can replace the all purpose flour with a 1:1 gluten free all purpose flour
Replace the chocolate chips with chopped walnuts or pecans for an added crunch
You can use chopped chocolate or white chocolate chips in place of regular chocolate chips