Preheat oven to 375 Degrees.

Butter a large casserole dish and set aside.

Prick each washed potato with a fork several times, to allow steam to release. Place the potatoes in a baking pan and roast for about 30 minutes until soft. Larger potatoes will take longer.

Remove the sweet potato pan from the oven, and add the unpeeled bananas to the baking pan, with the potatoes. Allow the potatoes and the bananas to roast together on the pan for an additional 10-15 minutes, until the potatoes are very soft to the touch and the bananas have darkened. Remove the pan from the oven, but leave the oven turned on.

When the sweet potatoes are cool enough to handle, using a spoon, scoop the sweet potato flesh into a large bowl. Add the peeled bananas, 1 stick of the butter, honey, vanilla and salt to the bowl. Beat vigorously with a wooden spoon until the mixture is smooth and fluffy.

Spoon the sweet potato mixture into the large greased casserole dish and smooth the top with a spoon.

In a medium bowl, combine the flour, brown sugar, pecans and remaining stick of butter until the mixture resembles coarse crumbs.

Sprinkle the brown sugar and nut mix over the sweet potato mixture and place the casserole in the oven for 20 minutes. The crumbs will be golden brown when the souffle is done. Serve hot and enjoy!