Spray an 8×8 pan with Baker’s Joy® No Stick Spray with Flour then line it in both directions with parchment paper that extends beyond the edges of the pan; set aside.
In a large bowl, combine the flour, powdered sugar and brown sugar.
Add the melted shortening and melted butter and stir until a dough is formed.
Press the mixture evenly into the prepared pan and bake for 15 minutes.
Allow to cool slightly while preparing filling.
Lime Filling
In a medium bowl, whisk together the eggs, granulated sugar, flour, lime zest, lime juice, baking powder and food coloring (if using) until well blended.
Pour over the baked crust.
Return to a 350˚ F oven and bake for 20-22 minutes.
Cool in the pan on a wire rack.
White Chocolate Topping
In a microwave safe cup or bowl, combine the white chocolate chips and the shortening.
Microwave for 30 seconds then stir.
microwave for an additional 30 seconds and stir until smooth.