Adjust the oven shelf to the middle position, preheat the oven to 180°C and line a 20cm (8”) square baking tin with baking paper cut large enough to overhang the sides of the tin (to help you remove the baked brownies).

In a heatproof bowl over a pan of simmering water, melt the dark chocolate and butter together. Set aside to cool until warm.

Using a stand mixer with the whisk attachment or a hand mixer fitted with the double beaters, whisk the eggs and sugar on medium-high speed for 5-7 minutes until pale, fluffy and about tripled in volume. The mixture should briefly pile on top of itself as it falls off the whisk.

Pour in the melted chocolate while whisking on low speed, then increase the speed to medium-high and continue whisking until all the chocolate is fully incorporated.

Sift the gluten-free flour blend, cocoa powder, xanthan gum and salt into the egg-chocolate mixture, and use a spatula to gently fold in until no clumps remain.

Transfer to the lined baking tin, smooth out the top, and bake for about 30-35 minutes (30 minutes for gooey; 35 for fudgy) or until an inserted toothpick comes out with some half-baked batter attached (gooey) or with some moist crumbs attached (fudgy).

Cool the brownies completely to room temperature before taking hold of the baking paper and removing them from the tin. Use a sharp knife of the baking paper and removing them from the tin. Use a sharp knife to slice into portions (cooling allows the crumb to set to give you clean slices with neat edges).

If you want to serve the brownies warm (for example, with a scoop of ice cream), reheat them in the microwave for about 15 seconds.

Store in a closed container at room temperature for 3-4 days.