I found this recipe on Betty Crocker’s Gluten Free Website.  They are very easy to make and delicious!

Here is the link to the recipe: Gluten Free Cookie-Brownie Bars.

I do not use butter in my Betty Crocker GF Mixes, I use Smart Balance and have noticed that it makes a huge difference in the texture of the final product because it is comprised mostly of oils, which contributes to a moist crumb in the final product.