1. Bring a large pot of lightly salted water to a boil.
2. Add pasta and stir gently.
3. Return to the boil for 8 to 10 minutes or until al dente.
4. Remove from heat and add 1 cup of cold water to stop the cooking. Drain well.
5. Coarsely chop the onion, olives, yellow pepper, and sun-dried tomatoes.
6. I prefer to shred the fresh spinach by hand, and again if using baby spinach, just tear it into 2 or maybe 3 pieces.
7. Combine pasta with chopped vegetables, spinach, and crumbled feta.
8. Add the oil, vinegar, salt, and pepper.
9. Toss and chill for a minimum of 1 hour in the refrigerator.
10. This can be made ahead of time and refrigerated for a few days.

I love the leftovers, if you have any, as the flavor intensifies overnight. I have made this many a time and everybody just loves it and always asking for more.

Original source: melissamayo