This is a Hungry Girl recipe (be sure and sign up for her emails if you don't already get them). She always has great recipes in her newsletter and in her cookbooks like Hungry Girl 1-2-3: The Easiest, Most Delicious, Guilt-Free Recipes on the Planet that are diet friendly. This recipe makes 12 servings at 4 WW points each, plus it's super easy.
All you need is 1 box of moist devil's food cake mix, 1 cup of fat free plain Greek yogurt and 1 cup water.
Combine ingredients in a large bowl and add 1 cup water. Whisk thoroughly and transfer to a baking pan sprayed with nonstick spray; bake in the oven until a knife inserted into the center comes out clean. (Refer to cake-mix box for pan size and approximate bake time.)
I made a 9x13 cake and it turned out really good. I sifted a little powdered on the pieces I cut for the kids and they loved it. It was a great afternoon snack with some lemonade.