Saving 1/4 cup crushed graham crackers for the top mix the remaining with the melted butter and press into bottom of 9x13 pan.
Simmer in a sauce pan rhubarb, water, sugar, and cornstarch until rhubarb is tender (about 5 min.)
Spread mixture on top of graham crust and cool in fridge.
Mix together marshmallows and cool whip and spread on top of rhubarb mixture.
Mix up pudding according to directions on box, and before it sets pour on top of marshmallow mixture. Sprinkle remaining graham crackers on top. Keep in refrigerator until ready to serve. Enjoy!!
Not a NESTLÉ®-tested recipe.