Preheat the oven to 350 degrees F.
Combine all of the ingredients except the graham crackers and optional ingredients in a bowl, and mix thoroughly.
Place the mixture in a deep-dish pie pan sprayed lightly with nonstick spray, and bake in the oven for 45 minutes. (It will remain a little soft, like pie filling.)
Refrigerate until completely chilled and firm, at least 2 hours.
Top evenly with crushed graham crackers. Add whipped topping and cinnamon, if you like.
Serve and enjoy!
PER SERVING (1/8th of recipe, 1 slice): 144 calories, 0.5g fat, 110mg sodium, 30g carbs, 2g fiber, 26g sugars, 5g protein