Place one chicken breast on a cutting board, skin side up.
Pull the skin away from the meat, then discard skin.
Bone chicken breast.
Repeat with remaining breasts.
In a small mixing bowl combine Parmesan cheese and Italian seasoning.
Roll chicken pieces in cheese mixture to coat lightly; set remaining cheese mixture aside.
Arrange pieces in an 8x8x2 inch baking dish.
In a small saucepan cook onion in hot margarine or butter till tender but not brown.
Stir in flour, then add milk all at once.
Cook and stir till thickened and bubbly; stir in drained spinach and pimiento.
Spoon spinach mixture over chicken and sprinkle with remaining cheese mixture.
Bake, uncovered, in a 350° oven for 30 to 35 minutes or till tender.