Preheat the oven to 350°F (180°C). Line a 9-inch x 5-inch baking tray with parchment paper. You can also use a 9-inch x 9-inch square brownie pan, but the recipe will cook faster and the brownie will be thinner. Set aside.
Step 1: Prepare the flax egg
In a small mixing bowl, stir 1 tablespoon of flax meal with 3 tablespoons of hot water. Set aside 15 minutes until gooey and an egg-like texture appears. Use in step 3 when the recipe calls for flaxseed egg.
Step 2: Prepare the grated zucchini
Finely grate 2 large zucchinis, skin on, with their ends trimmed, with the thinner grater option on your hand grater, or using the thinner grating blade of your food processor.
Bring all the grated zucchinis into the center of a clean towel. Gather the extremities of the towel and twist to encase the zucchini into the towel and form a ball.
Twist as hard as you can until ALL the zucchini water is removed. This is extremely important or too much water will make the brownie too moist and fragile.
Measure 1 cup of packed, drained, grated zucchinis and transfer into a large mixing bowl.
Step 3: make the brownie batter
In the same mixing bowl, add runny peanut butter, flax egg (the one made in step 1), vanilla, maple syrup, and coconut sugar.
Stir the ingredients together until consistent. It is liquid and shiny.
Stir in the unsweetened cocoa powder, baking soda, salt, and melted coconut oil, making sure all the cocoa is incorporated and no lumps are left.
Now, stir in almond flour. The batter is getting thick and more difficult to stir. It is what you want.
Transfer the brownie batter into the prepared baking pan.
Bake for 30 minutes or until the top and sides are set, crackle, and a skewer inserted in the center of the brownie comes out clean or with few crumbs. Note that if you are using a wider pan, your brownie will bake faster. On the other side, a smaller pan will take longer to bake.
Remove the pan from the oven and cool down in the pan for 12 minutes.
Use a knife to loosen the sides of the brownies in the pan then use the parchment paper pieces to lift out the brownie from the pan to a cooling rack.
Cool for 30 minutes, then, to make it easier to slice and to make it even fudgier, pop it 10 minutes in the fridge! I know it sounds left field, but this will set the brownie to perfection, slice without breaking, and the fudgy texture will be enhanced.
Store in the fridge in an airtight box or ziplock bags or freeze individually. Defrost 3 hours before on a plate, on the counter at room temperature. Can be rewarmed in 2 minutes to serve lukewarm.
Swap almond flour for the same amount of oat flour or sunflower seed flour or sesame flour.
Replace peanut butter with sunflower seed butter, the same amount, use fresh seed or nut butter, runny and drippy!
Other flour options: you can use the same amount of fine oat flour in this recipe, but the brownies will be less moist and slightly denser. I didn't try all-purpose flour, it should work but may create a very dense and less fudgy result.Flaxseed meal replacement: you can use ground chia seed if desired to create a chia egg.