Preheat oven to 425°F and grease a 9-inch springform pan.

In a small saucepan, melt the butter. Once melted, remove from heat and whisk in the chocolate until smooth. Set aside to cool.

In a large bowl, whisk together eggs and sugar until foamy. Check that chocolate is cooled, then whisk into the egg mixture.

Gently fold in the flour and baking powder until incorporated.

Pour batter into prepared pan and bake for 12 minutes.

Let cool completely before serving. Dollop with whipped cream and tumble berries on top.