preheat oven to 350° . spray 9 x13 baking dish with. nonstick spray or grease well. arrange rhubarb pieces evenly in bottom bring sug. & water to boil in saucepan. add food color & set aside. blend the egg yolks, 1/4 of yogurt and the vanilla tog. place dry ingred in lrg mix bowl & blend at low speed.

add butter and rest of yogurt & beat on low for 1 1/2 min. until well mixed

on low speed, add egg yolk mixture a third at a x. pour & spread over rhubarb. the batter will be thick. pour warm syrup over cake.. bake for about 50 min..toothpick test in several areas .

to make sauce.......

blend sour cream with rest of ingred. set aside. sauce is best cool but not cold.

cool finished cake for 10 min...then invert onto platter. allow cake to cool another 15-20 min before cutting

cake can be made in advance but best served warm. individual pieces can Bo rewarmed..about 1 min on Med heat