-I like using a home made brownie instead of the box mix. If using a box mix, I think Ghiradelli is the best mix. Katie prefers it as well. -You may use Double Stuff Oreo's for the "full strength" version. -As for the caramel layer, it's optional. You may use a good quality caramel topping such as Mrs. Richardson's or I love Tom's brand available online, or if you live in Btown, sold at Dick's Market and other local grocers. OR, you can slowly heat a can of sweetened condensed milk (not evaporated milk) at a very low temperature, until the milk turns thick and caramel color. See directions and a few different methods for this here. I used the sweetened condensed milk route, and think in the future, if I'm adding the caramel layer, I'll just use Tom's.