Place the butter in a small pan, and the chocolate on top. Turn the heat on low and melt it together, while stirring with a wooden spatula. When melted and uniform, take it off the heat.
Place the eggs and sugar is a separate bowl and whisk together until the sugar is dissolved. Add the melted chocolate and whisk together. Add the flour and mix with a rubber spatula.
Fill 4 ramequins (7 cm diameter / 5 cm height), place 2-3 frozen raspberries in the middle of every ramequins.
Place the ramequins in a hot oven (180°C) for around 15 minutes. If you overbake them, they will no longer be ‘moelleux’, so watch them closely. If you take them out and shake and see that the centre is moving a little, it is time for them to leave the oven!