Preheat the oven to 350°F (175°C).

Line an 8x8-inch pan with parchment, leaving an overhang to lift the brownies out easily, and lightly grease the parchment.

In a medium bowl, whisk the melted butter and sugar until smooth.

Add the eggs one at a time, whisking until fully combined, then stir in the vanilla.

Sift together the cocoa powder, gluten-free flour blend, salt, and baking powder into the wet mixture.

Fold gently until just combined – avoid overmixing.

Fold in the dark chocolate chips (reserve a few to sprinkle on top).

For extra depth, stir in a pinch of espresso powder.

Pour the batter into the prepared pan and smooth the top.

Bake for 20–25 minutes. The edges should look set and the center will still be slightly gooey. A toothpick should come out with moist crumbs, not wet batter.

Let the brownies cool in the pan on a wire rack for at least 30 minutes before lifting out using the parchment overhang.

For clean slices, chill for 20 minutes and cut with a sharp knife warmed under hot water and dried between cuts.