Preheat your oven to 340°F (170°C). Lightly grease an 8x8-inch (20cm x 20cm) square baking pan with oil, then line it with parchment paper—leave a little overhang so it’s easy to lift the brownies out later. Trust me, future-you will thank you.
Melt the butter and dark chocolate together in a heatproof bowl—either over a double boiler or in the microwave (just go in short bursts and stir in between so nothing scorches). Once melted and smooth, stir in the sugar and warm milk. Whisk it all together until the sugar mostly dissolves.
Now add your dry stuff: flour, cocoa powder, baking powder, and salt. Whisk it in gently until the batter is smooth and no streaks remain—don’t overthink it.
Pour that rich, chocolatey batter into your prepped pan and spread it out evenly. Bake for 25 to 30 minutes, or until the top looks set and the center doesn’t jiggle. Let it cool a bit before digging in (or at least try to).