Wash the asparagus and cut off the woody ends generously. Cut the asparagus into thin strips. Cook tagliatelle according to package instructions in plenty of boiling salted water until firm to the bite.
Wash and quarter the tomatoes. Peel onion and garlic. Chop the onion finely. Cut garlic into thin slices. Roast pine nuts in a pan without fat until golden brown. Take them out. Heat the oil in the pan.
Fry the onion and garlic until transparent. Add tomatoes and fry for 3-4 minutes, then add asparagus and fry for about 2 minutes. Season with salt and pepper.
Wash basil and shake dry, chop leaves roughly. Take off about 100 ml of the pasta water, add to the vegetables and bring to the boil briefly. Mix pasta, vegetables, basil and pine nuts. Season with salt, pepper and 1 pinch of sugar.
Serve sprinkled with parmesan.