Dark Chocolate Zucchini Muffins/Cupcakes

1. Preheat the oven to 375 degrees F. Prepare a 12-cup muffin pan with paper cups or cooking spray.
2. Grate the zucchini. Wrap the grated zucchini in paper towel or cheesecloth, and very gently squeeze to release extra liquid. You want the zucchini to be moist (this will help keep the muffins/cupcakes moist) but not dripping wet.
3. In a mixing bowl, whisk together the flour, cocoa, baking soda, espresso powder and salt, until well-combined. Set aside.
4. In another large mixing bowl, whisk together the sugar, oil and egg until very smooth and completely combined. Stir in the vanilla, followed by the zucchini. Gently fold in the flour mixture, and stir until just combined.
5. Scoop the batter into the prepared muffin pan, and bake for 17-19 minutes, until the muffin tops look set, and a cake-tester inserted into the center comes out clean. Remove from the oven and let cool in the muffin pan for 5 minutes before transferring the muffins to a baking rack to cool completely.

Dark Chocolate Mascarpone Buttercream Frosting

1. Sift the powdered sugar and cocoa powder. Set aside.
2. In a stand-up mixer fitted with the paddle attachment, beat together the butter and mascarpone on medium speed until light and fluffy, about 4 minutes. With the mixer on the lowest speed, add the powdered sugar and cocoa powder, about 1/4 cup at a time, until completely combined. Gradually increase the mixer speed to medium high. Add the milk and vanilla and mix until the frosting reaches your desired consistency. The frosting should be creamy but hold its shape.
3. Immediately frost the (completely cooled) chocolate zucchini cupcakes, using a knife to spread, or a pastry bag to pipe on the frosting in the style of your choice. I used a #2d flower pastry bag tip for the frosting shown here.