*Feta cheese should be finely crumbled. either by hand or in blender.
Cover chicken with cold water & simmer until tender, (about 1 hour) with salt & pepper, celery flakes & minced onion.
Cook manicotti according to pkg. directions & drain. Take olive oil & butter & heat; add bread crumbs & garlic powder. Beat eggs with fork & add cheese, drained spinach, chopped chicken, cream & salt. Mix this with bread crumb mixture. Should be of spreading consistancy.
Fill manicotti with this mixture; arrange in shallow baking dish; pour some spagetti sauce over before heating. Bake in 350 oven for 35 minutes. Serve with additional sauce.