PLACE meat, squash, pineapple and onions in slow cooker.
TOP with Simmer Sauce; cover.
COOK on LOW 6 to 8 hours (or on HIGH 3 to 4 hours).
15 Min. Before Serving
REMOVE liquid with ladle from slow cooker; set aside.
STIR in Finishing Sauce and spinach. Add some of the reserved liquid to desired consistency. Cook, covered, on HIGH 15 min.