Poke the sweet potatoes with a fork or knife a few times. Wrap each sweet potato in foil and bake in the oven until tender. Roughly 1 hour.
Remove from the oven and cool about 15 minutes.
Reduce oven temperature to 375F.
Spray a 9x13 dish with cooking spray.
Unwrap the sweet potatoes, cut open, and scoop out the cooked sweet potato.
Place in a large bowl. Add the cream, sugar, butter, milk, eggs, vanilla, and salt.
Mix to combine.
Spread into prepared casserole dish.
In a medium bowl, combine the cornflakes, pecans, light brown sugar, and butter.
Spread mixture over the sweet potatoes.
Bake uncovered for 20 minutes.
Remove and sprinkle with miniature marshmallows.
Return to oven and cook another 3-5 minutes. Or you can broil for 1 minute to toast the marshmallow and get it a light golden brown versus just melting them. (Watch carefully)
Remove and serve warm.