1. Cook pasta according to packet directions. Drain..
  2. While fettuccine is cooking, steam snake beans for 4-5 minutes.
  3. In a non stick pan, heat oil and gently fry prawns for 3 minutes, turning frequently until flesh is pink (do not overcook).
  4. Add beans, asparagus, capsicum and juices and bring to the boil. Simmer, uncovered, for 2 minutes.
  5. Add mandarins and lemon thyme.
  6. Drain fettuccine and add sauce. Toss well together and serve at once.