In a large bowl, whisk together the butter and sugar. Gradually add the flour, then add the eggs one by one until the dough is well combined and starts sticking to the sides. Scrape down the sides of the bowl, then fold in the nuts and chocolate chips. Whisk again until you get an even dough.
Flatten the dough, wrap it in cling film, and refrigerate for an hour.
Divide the chilled dough into 15 equal portions (+/- 90g) and roll each of them into a ball. Refrigerate the balls for another 2 hours.
Preheat the oven to 180° fan & line a sheet pan with parchment paper.
Place 4 dough balls on the prepared sheet pan and bake for 12 minutes. Let cool for 5 minutes, then transfer to a wire rack to let cool a little more. You can either enjoy them still warm or completely cooled down.
Enojoy!!!