Wash the asparagus, cut off the woody ends. Cut the asparagus into pieces. Wash rocket, shake dry. Wash lemon hot, grate dry, cut peel into thin strips with a zest ripper. Halve the fruit, squeeze the juice.
Cook the pasta in boiling salted water according to the instructions on the packet. Add the asparagus for the last 4 minutes. Mix cheese, 2-4 tablespoons lemon juice, 100 ml pasta boiling water, season with salt and pepper.
Pour the noodles into a sieve and put them back into the pot. Stir in the sauce. Serve the noodles. Sprinkle with lemon remains and rocket.