Combine the first cup of sugar listed with the flour, baking powder, shortening, milk, salt and vanilla. Mix these ingredients well! Spread the mixture in an 8 x 8 (or similar) pan sprayed with cooking spray. Top the batter with diced rhubarb. Combine the sugar and warm water and pour over the rhubarb layer. Bake at 375 degrees for at least 30-35 minutes or until batter begins to brown and a toothpick inserted in the center comes out clean. Top with real cream or vanilla ice cream...and ENJOY!