Preheat overn to 400F.
Grease an oblong baking dish.
Mix sauce ingredients in a sauce pan and cook until rhubarb is tender, almost falling apart. Use a potato masher if needed to help break down fruit. Set aside to cool slightly.
Combine 1.5 c sugar and 1.c of water in a saucepan, cook 5 minutes to create a simple syrup. Pour into the greased baking dish.
Mix the flour and baking powder together in a large bowl.
Cut in 1/3 c shortening
Knead a few times on a floured board, then roll out into a 12 inch square (or like me more rectangular 9 x 12").