This is a recipe that I've been eating or as far as I can remember and that everybody seems to enjoy.
1. Pre-heat the oven at 180°C
2. Melt chocolate and butter in the microwave
3. Add the eggs, the sugar, the flour, the melted chocolate and butter into a bowl
4. Mix everything so it becomes homogeneous
5. Pour the dough into the moulds at 3/4 (tip: use an ice cream scoop for this)
6. Put the moulds in the oven for 18 minutes
7. Wait 10 minutes before unmoulding them.
Yum.