Instructions:Preheat oven to 350 degrees F.Grease an 11X15 inch baking pan. Using a food processor, process the flour, powdered sugar and butter until it comes together to form dough–about one minute. Press the dough into the bottom of the pan and bake for 20 minutes.Dice the rhubarb. Process the sugar, eggs, vanilla and salt until thick. Add the flour and process another 10 seconds. Stir the mixture into the rhubarb and spread over the baked crust. Bake until the top is brown and firm, approximately 35-40 minutes. Cool completely and cut into squares. This recipe makes about two dozen squares depending upon the the size you cut them. If you don’t have a food processor, cut the dry ingredients and butter in with a whisk attachment on your electric mixer (it must form the dough)and also process the rhubarb and egg mixture with a electric mixer. These pastries are brilliant with the almost crisp thin shortbread-style crust and the rhubarb, nicely sweetened and baked into the egg mixture.