Agreed as if you burn the chocolate, it's very tough to get out of a steel pan.., so more so I should think getting it off cast iron....is it not more porous than steel?
It may also depend on what the filling is to be, when done?
I mean if you are going for a sort of very damp brownie that's going to be different than a chocolate soufflé, and both are different than what I imagined when you wrote "chocolate cobbler".
I envisioned a sort of thick, chocolate pudding for filling, topped with a brown, lattice crust.
:idunno:
You might get away with making chocolate pudding, then pouring it into the Dutch oven, which was preheated to about the same temp as the pudding. Then very quickly cover with the crust and place the Dutch oven lid on top, and ONLY put coals on the lid, to brown the crust.
I'd try it with a round, aluminum, disposable casserole pan inside the oven first. If it doesn't burn then maybe try it in the naked Dutch oven.
LD