DIRECTIONS: Preheat the oven to 350 degrees. Lightly grease a 9 by 13-inch pan and set aside. To make the filling: In a medium saucepan over low heat, cook the rhubarb, water, and sugar until bubbling. Then add the cornstarch and stir until the cornstarch is mixed throughout and the mixture has thickened. Add the almond flavoring and stir. Keep on the stove over low heat.
Recipe by Amish 365 at https://www.amish365.com/homemade-rhubarb-squares/