Preheat the oven to 350°F / 175°C. Grease a standard 8-inch square baking tin or a loaf pan, or line it with parchment paper.
Peel and slice the avocado. Put avocado flesh in a food processor. Add eggs and vanilla extract, and pulse until smooth.
Transfer the avocado mixture into a medium bowl. Add sieved almond flour, sieved cacao powder, sweetener, and baking soda. Mix using an electric mixer until you have a smooth mixture.
Chop the chocolate and put it into a microwave-safe bowl. Add coconut oil. Heat in one-minute intervals and stir each time until completely melted and smooth.
Add the chocolate mixture to the avocado mixture and combine well with a rubber spatula.
Transfer the brownie batter into the baking tin and optionally top with chocolate chips.
Bake for 30 minutes. Cool on a wire rack, slice into 8 pieces, and serve.
Notes
Add some mint leaves. It pairs perfectly with chocolate.Don't hesitate to add some crushed nuts to the batter for that additional crunch.