Preheat oven to 175°C.
In a bowl combine chocolate and butter and melt it in MW or a double boiler.
Keep it aside.
Add vanilla to eggs and whisk until combined. and set it aside for 10 minutes.
In a large bowl, combine together flour, cocoa powder and powdered sugar.
Add the egg and chocolate mix and whisk to combine.
Add the dry ingredients and mix.
Use a spatula to fold the batter.
Line a 8"square cake tin with parchment and grease it well.
Let the paper hang outside the tin which will help you to remove the brownies later.
Transfer batter to the tin and top with almonds, choco chips and walnuts.
Bake for 45 minutes until a toothpick comes out clean.
Refrigerate for 20 minutes before removing the brownie from the pan.
Trim the sides and slice it into 16/36 equal squares with a knife.