Cook the pasta according to the packet instruction.
Thinly slice the onion. Heat the oil in a large frying pan and gently sauté it until soft, stirring regularly.
Add the balsamic vinegar (with honey if needed) and let it bubble for a minute or so until it reduces.
Crumble most of the cheese into a small bowl. Add a 1-2 Tbsp of the pasta cooking water and mix well.
When the pasta is ready, drain and add it to the onion together with the cheese sauce.
Toss well, then serve onto two plates.
Crumble the remaining cheese on top, then scatter the nuts and the herbs around and season with pepper.
Serve warm.