Cook, chop & drain spinach. Set aside. Cook & mash potatoes; add sour cream, sugar, butter, salt & pepper. Beat until light and fluffy. Add chives, dill and spinach. Place in a greased casserole and sprinkle with cheese. Bake at 400° for 20 minutes.
Can be made ahead and refrigerated; allow a little longer baking time.
-from Tonya Smith