Preheat the oven to 350°F (175°C). Line an 8x8-inch baking dish with parchment paper or grease it.

Melt the chocolate and butter together in a microwave-safe bowl, microwaving in 20-30 second intervals, stirring after each, until smooth. Alternatively, melt them on the stovetop over low heat.

Whisk the eggs in a separate bowl until well beaten.

Once the chocolate and butter mixture has cooled slightly, pour it into the eggs and stir until combined.

Pour the batter into the prepared baking dish and spread it evenly. Bake for 20-25 minutes or until a toothpick inserted into the center comes out with a few moist crumbs.

Let the brownies cool for at least 10 minutes before cutting into squares. The longer they cool, the firmer they will set.