Not to contradict your test kitchen but I disagree that the best result is to cook the whole meal part of the way and then remove the fully cooked brownie. This lets the brownie get cold and ends up with two different serving dishes.
I found it was much better to pull the frozen dough out of the dish, cook the rest of the meal for the "difference" amount, then put the brownie in and cook the whole thing together.
Cooking good!
Best Regards,
William Li
