Preheat the oven to 375°F (190°C). Line and grease an 8-inch round cake pan.

Melt the dark chocolate in a microwave-safe bowl or double boiler until smooth.

In a separate bowl, whisk together eggs and sugar until light and fluffy.

Fold the melted chocolate into the egg mixture until just combined.

Pour the batter into the prepared pan and bake for 25-30 minutes, or until a toothpick comes out with moist crumbs.

Allow the cake to cool completely before serving, dusting with powdered sugar or topping with fresh berries if desired.