1. Cook pasta according to package directions. Drain and rinse under cold running water and drain again. Place in large bowl and toss with cider vinegar. Set aside for about 10 to 15 minutes.
2. Add green pepper, celery and red onion. In small bowl, combine mayonnaise, yogurt, mustard, salt and pepper. Add to pasta mixture and toss to coat. Gently stir in eggs, cheese and tomatoes. Cover and refrigerate until ready to serve, for up to 8 hours.
Tip: The dressing of ½ mayonnaise and ½ yogurt reduces calories as well as adding a tang to the salad, but can easily be made with all mayonnaise.
Tip: Omit cheese for a variation, or substitute cheddar with your favourite strong cheese.