Preheat the oven to 180 ° C. Line a muffin tin with 12 paper cases.
Melt the butter, chocolate and sugar in a saucepan, stirring occasionally, until a uniform mixture is formed. Remove the pot from the oven.
Sift the flour and fold it into the chocolate mass. Then add the eggs and stir in vigorously. Pour the dough into the molds and bake for about 30 minutes.