Preheat oven to 176°C | 350°F. Line a 8x8" baking pan with baking?parchment paper, or lightly grease with oil spray. Set aside.
In a medium bowl, whisk together the zucchini, butter, oil, egg, sweetener (or sugar), and vanilla until well combined. Add the peanut flour, cocoa powder, baking powder and salt; folding through slowly until just combined. The batter will be thick but shouldn't be dry. (It depends on how much liquid your zucchini has! If too dry, add 1-2 tablespoons of water). Fold in half of the chocolate chunks; pour batter into prepared pan; sprinkle remaining chocolate chunks over the top.
Bake for 30 minutes or until the brownies spring back when gently touched. (If testing with a toothpick, they will be very moist in the centre BUT they do set and harden when removed from the oven.)
Allow to cool completely (about half an hour); cut into squares and chill to semi-set.
If storing at room temperature they're best eaten within 2 days. If refrigerating, they last 3-4 days.
Notes
I use a sweetener that measures 1:1 with normal sugar. If using a stronger sweetener, measure the amount needed for 1/3 cup normal sugar. Do NOT substitute the peanut flour with almond flour! The texture will be altered, dried out and wrong! Please, FOLLOW THE RECIPE.