Grease one 9x13-inch casserole dish.
Preheat oven to 350 degrees F (175 degrees C).
In a large mixing bowl, combine the sweet potatoes, 1 stick melted butter, sugar, heavy cream, eggs, ½ teaspoon salt, vanilla extract, and cinnamon.
Using a handheld electric mixer beat until smooth.
Spread evenly in prepared casserole dish.
Prepare the topping by combining the butter, salt, brown sugar, flour and pecans.
Mix well until crumbly, and sprinkle evenly over sweet potato mixture.
Bake for 30 to 40 minutes, or until golden and toasted in the preheated oven.