1. Cook pasta according to packet directions, then drain.
  2. Heat a small pan and gently pan-fry the tuna in some olive oil for 2 minutes.
  3. Add the onion, garlic, mushrooms, snow peas and chilli, fry for 2 minutes.
  4. Add chicken stock and simmer for a minutes to reduce.
  5. Remove from the pan and combine with pasta in a large mixing bowl.
  6. Gently toss through the lemon juice and lemon thyme.
  7. Add salt and pepper to taste.