In a large saucepan, saute onion in butter until tender. Stir in the flour, salt and pepper until blended. Gradually stir in broth; bring to a boil. Boil and stir for 2 minutes or until thickened and bubbly. Stir in the cream, chicken, rice, mushrooms, pimientos and parsley; heat through.
Transfer to a greased 2-1/2-qt. baking dish. Sprinkle with almonds. Bake, uncovered, at 350° for 30-35 minutes or until bubbly.