Preheat your oven to 325°F and line baking sheets with parchment paper. While the oven heats, melt the 2/3 cup chocolate chips using a double boiler or microwave in 30-second intervals, stirring between each burst to prevent scorching. Once melted, transfer to a small bowl and let cool to room temperature—this step is important because adding warm chocolate to the butter mixture can cause the dough to become greasy.

In a medium bowl, whisk together the flour, cocoa powder, baking soda, salt, espresso powder, and cinnamon. The espresso powder is a secret weapon—it deepens the chocolate flavor without making the cookies taste like coffee. Set this dry mixture aside.

In a large bowl, beat the softened butter with both sugars for 1-2 minutes until light and fluffy—this incorporates air into the dough, making the cookies tender. Add the room-temperature egg and vanilla extract, beating until fully combined. Fold in the squeezed-dry zucchini gently but thoroughly; the zucchini adds moisture and a subtle vegetal sweetness that balances the chocolate richness.

Add the cooled melted chocolate from Step 1 to the butter mixture from Step 3, stirring until fully incorporated and the dough has a rich chocolate color. This creates a cohesive base before adding the remaining ingredients. Now gently fold in the dry ingredient mixture from Step 2 until just combined—avoid overmixing, as this keeps the cookies tender. Finally, stir in the 1 1/4 cups semi-sweet chocolate chips until evenly distributed throughout the dough.

Using a cookie scoop or spoon, drop rounded portions of dough onto the prepared baking sheets, spacing them about 2 inches apart to allow for slight spread. I like to slightly flatten each dough ball with the back of a spoon—it helps them bake more evenly and gives a more uniform thickness. Bake for 10-11 minutes; the cookies should look set on the edges but still slightly soft in the center when you remove them from the oven.

Allow the cookies to cool on the baking sheet for 5 minutes to set, then transfer to a wire rack to cool completely. This resting time on the pan prevents them from breaking apart, which is especially important for these chocolate-heavy cookies.