Cook the diced vegetables and the pasta in boiling water for 10-15 minutes (depending on your chosen pasta).
Dry-fry the pine nuts and set aside.
Finely chop the onion, mince the garlic and slice the sage. Heat a little oil, add the onion and sage slices. After 3 minutes, add the garlic and cook for a couple of more minutes until light brown.
Drain the pasta and vegetables into a large bowl. Add the onion mixture, the pine nuts and chilli flakes. Mix in the cheese (if used).
Season with salad and pepper to taste.
Serve warm.