Taffy Apple Salad

Drain pineapple (reserve liquid). Core apples, cut in half and scoop out seeds with melon baller. Cube apples (1/2-inch cubes). Beat egg. In small saucepan, combine pineapple juice, egg, sugar, flour and vinegar using a wire whisk. Over medium heat, stir with a wooden spoon until thickened. Pour mixture into large mixing bowl. Cool. Cover with plastic wrap and refrigerate. When thoroughly cool, fold Cool Whip into cooked mixture and add 1/2 cup peanuts.