Melt together your hard margarine and dark chocolate over a bain marie until completely melted. Mix together and leave out to cool down to about 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 golden 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 about 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 9" 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 20 minutes at 175C fan.
Remove from the oven and add 5 halved Creme Eggs, ensuring that each brownie slice will get one. You can also add a few mini Creme Eggs if you fancy!
Bake for another 12 1/2 minutes mins. Cooking for this amount of time at this temp should create incredible fudgy brownies.
Important!! Allow to cool completely before touching them!! Slice them up and enjoy!