In a cup, make 3 "Chia eggs" by mixing the milled chia seeds with water and letting it sit for 5 minutes, it will turn into a goopy, egg-like texture.
Add avocado flesh, unsweetened applesauce, chia eggs and vanilla extract to your blender or food processor and blend until smooth.
Mix in xylitol, coconut flour, unsweetened cocoa powder, sea salt and gluten-free baking powder and mix until well combined.
Line an 8x8 inch baking dish with baking paper and add the batter.
Place in oven to bake for 30 minutes (slightly less for fudgier brownies or slightly longer for more cake-like brownies). You can insert a wooden skewer into the centre to test if the brownies are done, if it comes out mostly clean with only a view dry crumbs sticking to it it's fine. In case there is wet dough clinging to it you want to bake it for approximately another 7-8 minutes.
Let cool completely before adding the frosting.
Cashew nut butter frosting
In a small bowl, make the frosting by mashing the avocado with a fork very well. Stir in the cashew butter and maple syrup and mix again. Add the cacao powder and coconut milk. Mix everything together until it’s smooth.
Put the frosting into the fridge to firm up until the brownie has cooled completely.
Spread the frosting on top of the brownies with a spatula, cut the brownie into 9 squares and enjoy.