I have fine-tuned this for 2 decades and have served it for a crowd at Realtor luncheons with rave reviews. I was inspired years ago by the chicken salad at one of my favorite restaurants in Lincoln, Nebraska -- "Kay's" in the Piedmont Shopping Center (Terms of Endearment filmed there) and I'm afraid it is now closed.
Bring a large saucepan of water to boil and add 1/2 t. salt. Add the chicken breasts and boil for 5 minutes until cooked through. Cut into large 2 to 3 inch chunks and let cool.
In the meantime, mix mayonnaise and plain yogurt together. Add salt, garlic powder, chopped shallots, and dill weed. Let blend together for a few minutes.
Once the chicken chunks are cool to touch, start shredding them into small strips -- NO CHUNKS! I am serious -- the shredded chicken gives this salad a wonderful texture. It will take some time, but it's worth it.
Stir shredded chicken into the mayonnaise mixture and fold until completely blended. It's best served a few hours later (to blend flavors), but you can serve immediately if you wish.
Cut croissant rolls almost in half, place several leaves of lettuce on the bottom, top with chicken salad and sprinkle with cashews. Yum!!