In a small bowl mix all topping ingredients together and set aside.
In a bowl mix well the mashed sweet potatoes with white sugar, salt, beaten eggs, and butter.
Whip the cream and add vanilla and cinnamon, then put in little by little the sweet potato mixture and mix everything from the bottom to the top.
Pour into a greased casserole, cover with topping.
Bake at 350°F (176,6°C) for 30 minutes.