Preheat the oven to 170°C (fan 150°C) / 340°F / Gas Mark 3.
Line the base and sides of a 28 x 20cm (11 x 8 inch) rectangular baking tin with baking parchment.
Place the chopped HU Vanilla Crunch chocolate and butter in a heatproof bowl over a pan of gently simmering water. Stir until melted and smooth, ensuring the bowl doesn't touch the water.
Remove from the heat and stir in the caster sugar until fully combined.
Add the gluten-free flour and mix until smooth.
Beat in the eggs one at a time until the mixture is glossy, thick and well combined.
Fold in the nuts or chocolate chips, if using.
Pour the mixture into the prepared tin and smooth the surface.
Bake for 28–32 minutes, until the top is shiny and crackled but the centre still has a slight wobble. Gluten-free brownies can dry out if overbaked, so it's better to slightly underbake them.
Leave to cool completely in the tin before cutting into squares.
Dust lightly with icing sugar before serving, if desired.
Caroline's Tip: These brownies are delicious made with HU Vanilla Crunch chocolate, which adds subtle vanilla notes and crunchy cacao pieces. Reducing the sugar to 200g creates a richer chocolate flavour without making them overly sweet. They're even better the next day once the flavours have developed.
