Melt together your dairy free hard margarine and dairy free dark chocolate over a bain marie until completely melted. Mix together and leave out to cool down to room temp.
Sieve together your cocoa powder and gluten free flour in a bowl. Mix briefly until combined, put to one side.
In another bowl crack 3 eggs and pour in your caster sugar. Beat together (I use an electric hand whisk) until pale in colour and almost a little frothy.
Once the chocolate and margarine mixture is cooled to room temp, pour it into your egg/sugar mixture. Fold it in, it will initially marble and then turn super chocolatey.
Next fold in the your gluten free plain flour and cocoa powder mix. Ensure it's fully folded in.
Pour/spoon your brownie mixture into a prepared tin, smooth it over so it's even and level. (I used a square loose bottom tin with a little parchment/baking paper in the bottom)
Bake for about 25 mins at 175C. Cooking for this amount of time at this temp should create incredible fudgy brownies. (You can check them during cooking they may take a little less time)
Important!! Allow to cool completely before touching them!! Slice them up and enjoy!