Prepare the Zucchini: Start by washing the zucchini and grating it using the small side of a box grater. The shreds should be soft and fine so they blend easily into the batter. If the zucchini feels very watery, gently press it with a paper towel to remove excess liquid.
Preheat the Oven and Prepare the Pan: Set the oven to 350°F (175°C). Line a small baking pan with parchment paper or lightly grease it with oil. Preparing the pan early helps the batter go straight into the oven once it is ready.
Mix the Dry Ingredients: In a large bowl, combine the flour, cocoa powder, baking soda, and salt. Stir everything together until the mixture looks evenly blended and the cocoa powder spreads throughout the flour.
Combine the Wet Ingredients: In another bowl, whisk the egg, maple syrup, sugar, yogurt or applesauce, melted oil, and vanilla extract. Stir slowly until the mixture looks smooth and slightly glossy.
Create the Batter: Pour the wet ingredients into the bowl with the dry ingredients. Stir gently with a spatula until the mixture forms a thick chocolate batter. Avoid mixing too aggressively so the brownies stay soft after baking.
Fold in the Zucchini: Add the grated zucchini and optional chocolate chips or nuts. Stir carefully so the zucchini spreads evenly through the batter. At this stage the batter may look slightly thick, yet the zucchini releases moisture during baking.
Bake the Brownies: Spread the batter evenly into the prepared baking pan. Bake for about 20 to 25 minutes, until the top looks set and a toothpick inserted in the center comes out with a few moist crumbs.
Cool and Slice: Allow the brownies to cool in the pan for at least 10 to 15 minutes. Once cooled slightly, lift them out using the parchment paper and slice into squares for serving.
