Mix all layer 1 ingredients together in a medium sized bowl then press into a 9x13 baking dish to form a bottom crust. Bake at 350 degrees for 10 minutes.

Cool layer 1 in the refrigerator while you mix up layer 2. Carefully spread the thick vanilla frosting over the bottom layer. Cool the first two assembled layers in the refrigerator for at least 2 hours, until the vanilla layer is hard and cold.

For the third layer, melt the chocolate chips in a 2 cup glass measuring cup in the microwave, stirring every 30 seconds until melted and smooth. Spread the melted chocolate over the vanilla layer, working quickly before the chocolate hardens.

Cool again in the refrigerator to finish hardening the top layer of chocolate. These bars are easiest to cut at room temperature.