Preheat oven to 375 degrees. Bake sweet potatoes for 45-60 minutes, or until easily pierced with a fork. Remove and allow to cool until able to handle.
Cut sweet potatoes in half, scoop out potato flesh and add to a large mixing bowl or the bowl of a stand mixer fitted with a paddle attachment.
Preheat oven to 400 degrees. Coat a 9x13 baking dish with cooking spray.
Add butter, mix well. Add eggs, one at a time, mixing well between each. Add milk, sugar, cinnamon and salt. Bake 15 – 20 minutes @400 degrees.
Place potato mixture into prepared 9x13 baking dish. Bake for 20 minutes. Remove.
Meanwhile, prepare pecan topping. Cream together butter and sugar. Add pecans.
Top sweet potatoes with marshmallows, return to oven for 5 minutes or until marshmallows start to melt. Remove.
Top marshmallow layer with creamed butter, sugar and pecans by using two forks and evenly placing over marshmallows.Finish by topping with Corn Flakes, gently pushing them into the mixture. Return to oven for 10-15 minutes, or until the top is lightly browned.
Remove and allow to rest for 10-15 minutes before serving.