Preheat oven to 180c. Grease 4 x 1 cup ramekins and place onto a baking tray.
Break chocolate into pieces and place into a small saucepan with butter and brown sugar. Melt over low heat until smooth. Cool for 5 minutes.
Lightly whisk eggs and egg yolks together and gradually stir into chocolate mixture with vanilla. Sift flour over and gently fold in.
Divide mixture evenly between ramekins. Bake for 20 minutes or until top is set but centre is still soft. To serve, simply drop a scoop of ice-cream into the centre and dust with cocoa.