Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Melt the butter in a saucepan or microwave, then stir in the sugar until combined.
Whisk in the eggs and vanilla extract until the mixture looks smooth and glossy.
Sift in the cocoa powder, flour, baking powder, and salt. Stir just until the dough forms.
Scoop out tablespoons of dough and roll into balls. Space them out on the baking sheet.
Bake for 8–10 minutes, or until the edges look set but the centers are still soft.
Let them cool on the tray for a few minutes before transferring to a wire rack (or your mouth).