1. 1. Preheat your oven to 350°F. Grease and line a baking tin with parchment paper.

2. 2. In a heatproof bowl set over a saucepan of simmering water, melt the butter and dark chocolate together until smooth and glossy. Remove from heat and let cool slightly.

3. 3. In a separate bowl, whisk together the eggs, caster sugar, light brown sugar, and vanilla extract until pale and fluffy.

4. 4. Gently fold the melted chocolate mixture into the egg mixture, being careful not to overmix. Sift in the flour, cocoa powder, and salt, then fold until just combined.

5. 5. Pour the brownie batter into the prepared baking tin and bake for 25–30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Allow to cool completely before adding the pistachio coating.

6. 6. Spread the warmed pistachio cream evenly over the cooled brownies, ensuring a smooth layer. Sprinkle the chopped roasted pistachios over the top, pressing them gently into the cream.

7. 7. Cut into squares and serve.