1 1/2 cups mashed sweet potatoes
1/2 cup white sugar
1 (2 ounce) package cream cheese, softened
1/4 cup butter
1/8 teaspoon salt
Preheat oven to 350 degrees F (175 degrees C).
Place the sweet potatoes in the pan with the sugar. Place the cream cheese over the sweet potatoes and sprinkle with salt. Cover, and refrigerate overnight.
While the sweet potatoes are chilling, in a medium bowl, beat the butter until fluffy. Stir in the sugar and salt. Mix into the cream cheese mixture until completely combined. Pour mixture into an 8x8 inch baking dish. Beat egg in a small bowl. Using a wire whisk, beat the cream cheese mixture into the butter mixture until smooth. Using a fork, fold in the salt. Spread over pie.
Bake in preheated oven for 25 to 30 minutes, or until a toothpick inserted into the center of the pie comes out clean. Serve warm or cold.