1. For thicker bars use a 9x9 inch pan and bake 5 to 10 minutes longer. Avoid overmixing after adding flour to keep bars soft. Swap cream cheese frosting for vanilla buttercream if preferred. Sprinkles that bleed less are best for mixing into the dough. Store airtight at room temperature 1 day or refrigerate up to 5 days and bring to room temperature before serving