Base-line an 8 inch (20 cm) non-stick square baking tin with baking paper.
Pre-heat the oven to180 C/350 F/Gas 4.
Melt the chocolate with the butter
In a heat-proof glass bowl, melt together the butter and chocolate by either setting the bowl over a saucepan of lightly simmering water (stirring frequently). OR in a microwave set at medium on 30 second bursts, stirring between each until well blended.
Set aside to cool slightly.
Mix the dry ingredients
Mix together the flour, cocoa, xanthan gum, baking powder, salt and sugars, making sure all lumps are broken down. TIP: weigh into an airtight container and shake vigorously.
Making the brownies
Break the eggs into a large bowl and add the vanilla extract (if using).
Beat the eggs thoroughly with a fork, until well blended in appearance.
Add the melted chocolate mixture and thoroughly beat into the eggs with a wooden or firm silicone spoon.
Add the dry ingredients and beat again with the wooden/silicone spoon until smooth and even.
Add the granola and beat through until evenly-distributed in the mixture.
Pour the batter into the prepared baking tin and spread it to the edges, ensuring an even surface.
Bake for 30 to 40 minutes until the top is crisp and a skewer inserted into the centre comes out almost clean with a few crumbs attached.
Remove from the oven and leave in the tin to cool completely.
In order to make the brownie easier to cut, place in the fridge to firm up (it will soften back to 'chewy-gooey' once brought back to room temperature).
Once cold, carefully remove the brownie from the tin and cut into 16 even squares. If you prefer your brownies identical or want to remove the crustier edges, use a sharp knife to trim the sides before cutting into slices.
Decorating the brownies is optional. However I opted to drizzle with melted dark chocolate and to dust with a sieved sprinkle of freeze-fried raspberry powder to complement the raspberry granola that I used.
* Note: nutritional information is an estimate & may vary according to portion size/ingredient variants.Gluten Free Alchemist Flour Blend A can be found on the GFA Flours & Flour BlendingPage. If using an alternative flour blend, the texture may be slightly different.The granola used to make these brownies should have a high ratio of nuts and fruit in the mix. Too high a content of oats or grains will affect the brownie texture. If the granola used is weighted towards grains and flakes, substitute a portion of the weight with extra toasted nuts.