Reserved frozen chicken curry, thawed
3 stalks celery, chopped (about 1 1/2 cups)
1 small red onion, chopped (about 1/2 cup)
3/4 cup mayonnaise
1 medium bunch seedless green grapes, halved (about 1 1/2 cups)
1 10-ounce bag baby spinach leaves
Thaw the frozen chicken curry in the refrigerator the day before serving.
In a large bowl, stir together the chicken curry, celery, onion, and mayonnaise. Season with salt and pepper and fold in the grapes and spinach.