Preheat the oven to 375°F. Cream together the sugars, shortening, chunky peanut butter, egg, and 1/4 cup butter until smooth.
Add the flour 1/4 cup at a time and mix until combined. On the last quarter cup of flour, add the baking powder, baking soda, and salt then stir until combined.
Grease a glass baking pan with cooking oil then spread the cookie dough across the pan in an even layer. Bake for 35-40 minutes or until golden brown. Let cookie crust cool completely.
In a small bowl, whip together the creamy peanut butter, confectioners sugar and butter until smooth. Spread the buttercream across the top of the cooled cookie crust.
In a small bowl, whip together the creamy peanut butter, powdered sugar, and butter until smooth. Spread the buttercream across the top of the cooled cookie crust.
Whisk together the jelly, remaining powdered sugar, and water until a thin jelly glaze is formed. Pour the glaze over the top of the buttercream.
Use a knife to swirl the glaze into the buttercream until the glaze streaks through the buttercream. Chill for at least two hours or until the jelly glaze is set.
Cut into evenly sized bars. Serve chilled or room temperature. Enjoy!