I don't know if it is a real dish; I couldn't find anything googling either.
What I gathered from the clip is that it's a spicy dessert.
The ingredients are: molasses, mango, banana, rutabaga, and chili.
They didn't chew much on it so I assume that the rutabaga was boiled down. I have never eaten it before but according to wikipedia it is a turnip like vegetable, but slightly bitter.
but it looked as tho there was enough consistency for light chewing(could of been the fruits tho).
Tommy Lee Jones mentioned chili after the other ingredients, followed by a cup of water.
So it is spicy, but yet the "creeps up on you" kind of spicy. (So it is boiled in with the rutabaga.)
Ok, I would first dice the rutabaga in 1 centimeter cubes then salt them. (I don't know how bitter it is so I would salt them if I thought the bitterness was overwhelming the other flavors.)
After that, I would rinse the rutabaga (so the dessert doesn't become salty).
Boil it in water with molasses brown sugar and chili powder. (If rutabaga is like other radish types it will absorb flavors well.)
I would boil it until the flavors soaked in well, but the rutabaga is still firm enough, so that if I poked it with a chopstick and lifted it, it wouldn't fall apart.
Next, I would use cornstarch and creme to thicken it a bit, then turn off the fire adding the banana and mango. Then let it cool naturally. (Both fruits are already soft so I would want to keep the consistency but slightly soften them by adding it into the mix right after I turn off the fire-) Then again, Samuel L Jackson said he reheated it a couple of times to get the flavor right; maybe he wanted a bit of the fruit flavors in the sauce as well. In this case, I would have 2 batches of banana and mango, the first would go in the pot with the rutabaga (it will probably melt), then the second batch at the end.
Instead of salting, I'd maybe boil the rutabaga once, taste the water and rutabaga, and if it is too bitter, dump out the water and reboil with fresh water, molasses, and brown sugar.
After it is cooled, refrigerate and serve cold! (The dishes weren't steaming.)