Preheat the oven to 170'C.
Melt the butter and the chocolate in a bowl over a pan of simmering water (bain marie).
Whisk the eggs and the sugar together. Once doubled in volume, gently fold in the chocolate, the flour and the pecan nuts.
Butter the silicone moulds and dust with flour. Pour the mixture into the moulds and cook in the oven for 10-12 minutes. Do not overcook the brownie as the centre should be gooey!
Remove from the moulds and serve when cool.
«Fold in the nuts of your choice - walnuts, pecan nuts or pistachios all work well.»