Preheat oven to 350°F. Spray bottom only of an 8x8 pan with cooking spray and set aside.
In the bowl of your mixer, beat cake mix, pudding mix, eggs, oil and lemon juice until a dough forms. Press the dough evenly into the bottom of your pan.
Bake for about 15 minutes or so -- until the edges are barely golden and the bars are puffy and firm on top. Remove from oven and let cool.
In a medium bowl, whisk together lemon juice and powdered sugar.