Preheat the oven to 180 degrees Celsius.
Melt the butter and the chocolate in a bowl over a pan of simmering water.
Whisk together the eggs and the sugar. Once this mixture has double in volume, add the melted chocolate and butter and then fold in the flour.
Pour the mixture into moulds and press a pecan nut into each brownie.
Transfer to the oven and cook for 6 minutes.
Once cooked, remove from the oven and allow to cool in the moulds.
«To make a delicious dessert, simply serve the brownies with a chocolate sauce or vanilla ice cream.»