Method

1. Cook the penne pasta in boiling water according to the instructions on the packet
2. Peel, wash and chop the red onion, tomato and basil, and drain the sweetcorn
3. Heat the oil in the frying pan and cook the chopped onion for 6 minutes, stirring occasionally until soft
4. Stir in the fresh tomatoes and cook for 2-3 minutes until heated through and beginning to soften
5. Drain the tuna
6. Add the tuna, balsamic vinegar, sweetcorn and basil. Heat for 1 minute
7. Stir in the pasta