1 Break the chocolate into pieces and melt with the butter in a water bath, stirring constantly with a spatula or wooden spoon. Remove the resulting thick chocolate sauce from the water bath and leave to cool.
2 Meanwhile, mix the eggs with a hundred grams of brown sugar: beat the eggs in a separate bowl and whisk, gradually adding the sugar. You can beat them with a mixer or by hand, whichever you prefer, but for at least two and a half to three minutes.
3 Chop the walnuts with a sharp knife on a cutting board. You can pre-fry them in a dry frying pan until fragrant, but this is not a necessary option.
4 In the cooled chocolate melted with butter, gently add the remaining sugar, then the flour and chopped nuts and mix everything well with a whisk.
5 Then pour in the sugar and egg mixture and mix thoroughly with the chocolate mixture. The color of the dough should be even and without streaks.
6 Preheat the oven to 200 degrees. Line the bottom of a small deep fireproof mold with a sheet of baking paper or tracing paper. Pour the dough into the mold. Place in the oven and bake for twenty-five to thirty minutes until the sugar crust appears.
7 Take the finished pie out of the oven, let it cool and cut it into squares with a sharp knife or pizza cutter - that way the slices will be especially even.
8 You can serve the brownies just like that, or you can sprinkle them with powdered sugar or arrange the squares on plates and decorate each portion with a scoop of vanilla ice cream.