Place pork slices in an ungreased 13-in. x 9-in. baking dish. Combine butter, thyme and cayenne; spread over pork. Pour 3/4 cup orange juice over meat. Bake, uncovered, at 425° for 20-25 minutes or until meat is no longer pink, basting occasionally.
Remove pork and keep warm. Pour pan drippings into a measuring cup; add enough remaining orange juice to measure 3/4 cup. Pour into a saucepan. Stir in flour and sugar until smooth.
Bring to a boil over medium heat; cook and stir for 2 minutes or until thickened. Serve with pork.