I made this recipe gluten free. Substituted the 1c regular flour for 1c king arthur gluten free flour + 1tsp xanthum gum. These are really yummy gf brownies. I also cooked the bottom half for 5 minutes less than the recommended. Not hard as rock the next day.
For me, the top brownie layer totally mixed with the caramel layer (unlike the picture). So, I pretty much have chocolate caramel flavor brownie topping. I was hoping for the ooey gooey yummy caramel flavoring. While the bottom layer was cooking, the top layer (waiting in the bowl), got really thick. Wondering if maybe it got too heavy and sunk into the caramel. If I try this again, I may split the recipe in half and make the top half after the bottom half is done.