Put the dark chocolate and butter in a microwave-safe container. Melt in the microwave at 800 W for 1 minute and 30 seconds. Add sugar, eggs and flour and stir until smooth.
Fill each of the MicroGourmet molds with the chocolate mixture and place a piece of chocolate in the center of each mold.
Fill the water tank with 400 ml of cold water. Place the micro-gourmet molds in the steamer and place on the water container. Close the steamer and cook at 800 W and stand for 5 minutes or 15 minutes at 600 W and stand for 10 minutes.
Then remove the lid and water container immediately to end the cooking process. Let cool for 15 minutes and remove from the molds.