Preheat the oven to 350°F. Line an 8-inch square baking pan with parchment paper or greased foil. Set aside.
In a medium bowl, sift together all the dry ingredients.
In a large bowl, whisk together all the wet ingredients.
Add dry ingredients to wet ingredients. Whisk until just incorporated, making sure no flour patches remain. Thoroughly press and fold in zucchini and chocolate chips, until zucchini is very well incorporated (about 30 seconds)—lightly smash the zucchini into the batter. The batter will be very, very thick—do not add additional liquids to thin out the batter.
Pour batter evenly into prepared pan. Using a rubber spatula, smooth batter into an even layer. The batter is very thick and sticky—you might need to grab a clean spatula to finish smoothing the layer. Optionally, press chocolate chips into the top of the batter.
Bake for 28-38 minutes. Mine took 35 minutes. Insert a toothpick to check for doneness—once it comes out clean with just a few moist bits, it’s done.
Allow to cool in the pan, placed on a cooling rack for about 1 hour. Lift out of pan, transferring brownies along with parchment paper directly onto the cooling rack. Allow to finish cooling for about 2 hours before slicing. Slice into 12-16 brownies. Enjoy!
A Note on Homemade Oat Flour: *If using homemade oat flour, make sure to blend the flour until very fine and sift the flour to remove coarse bits of oats that could create less than ideal results. Store until needed, then measure the amount required for the recipe.
Storing Notes: Store in an airtight container for up to 5 days in the refrigerator. Best the first 3 days. Heat in 10-second increments in the microwave to warm brownies before serving.
Nutrition Information: is an estimate based on the ingredients listed in Where to Buy Ingredients. Also, it’s estimated based on 16 servings per recipe, made without optional ingredients.