Best Sweet Potato Pie Ever!!!

This splendidly spicy, buttery rendition of the Old South Favorite is one of our new favs! You guys have to try it. Check out the crust recipe here too. Works great with this one.
Ingredients:
2 cups mashed sweet potatoes (about 2)
1/4 pound butter, softened
2 eggs, separated
1 cup packed brown sugar
1/4 teaspoon salt
1/2 teaspoon ground ginger
1/2 teaspoon cinnamon
1/2 teaspoon nutmeg
1/2 cup evaporated milk
1/4 cup white sugar
1 (9 inch) unbaked pie crust (find the one on this site it is easy and great)
Directions:
1. Preheat oven to 400 degrees F (200 degrees C)
2. In a mixing bowl, combine the sweet potatoes, butter, egg yolks, brown sugar, salt, ginger, cinnamon, nutmeg and evaporated milk. Mix together well. 
3. Beat egg whites until stiff peaks form; add 1/4 cup sugar and fold into sweet potato mixture.
4. Pour into pie shell and bake at 400 degrees F (200 degrees C) for 10 minutes. Reduce heat and bake at 350 F (175 degrees C) for 30 - 40 minutes or until firm.