Preheat oven to 350°F and line a muffin tin with 10-12 baking cups (and spray the inside of the cups with cooking spray for good measure). Set aside.

Shred zucchini and place in a colander lined with cheesecloth or paper towels over a bowl to catch the liquid. Gently press the zucchini to squeeze out excess moisture. Don't toss the leftover liquid just yet!

In a large bowl, combine flour, cocoa powder, espresso powder, baking soda, and salt. Set aside.

In a separate large bowl, beat together the sugar, applesauce and oil until completely combined.

Add yogurt, milk, and vanilla and beat until just combined.

Add the flour mixture to the wet mixture and beat until just combined.

Add shredded zucchini and stir to combine. If you're batter feels too dry, add some of the leftover zucchini liquid (a little at a time) and stir to combine.

Pour batter into prepared cupcake liners until they are about ¾ full (a little less if you want to stretch the batter to 12 cupcakes).

Place the cupcakes on the middle rack of the oven and bake for 15-17 minutes (or until a toothpick inserted in the center comes out clean).

Remove from oven and let cool in pan for a couple minutes before removing them and cooling completely on a wire rack.

Beat butter and cookie butter on high speed until combined and smooth.

Add powdered sugar, a little at a time, and beat on high speed until light and fluffy.

If the frosting is too thick, add milk a tablespoon at a time until it reaches the desired consistency.

Frost cupcakes and top with crushed Biscoff cookies. Enjoy!