Preheat the oven to 350°F (175°C). Prepare a square baking pan by lightly greasing it and lining the bottom and sides with parchment paper, allowing excess to overhang for easy removal.

In a large mixing bowl, whisk together the melted butter, brown sugar, and granulated sugar until smooth and fully combined.

Add the eggs one at a time, whisking thoroughly after each addition. Continue whisking the mixture for an additional 4–5 minutes until it becomes lighter in color and slightly thickened, which contributes to a crinkled brownie surface.

Stir in the brewed espresso and vanilla extract until evenly incorporated.

Add the cocoa powder, all-purpose flour, espresso powder, and salt. Using a spatula, gently fold the dry ingredients into the batter until just combined, taking care not to overmix.

Pour the batter into the prepared baking pan and spread evenly.

Bake for 30–45 minutes, or until the edges are set and a knife inserted into the center comes out mostly clean with a few moist crumbs.

Remove the brownies from the oven and allow them to cool completely in the pan. Once cooled, lift the brownies out using the parchment paper and slice into portions.