Combine sweet potatoes, brown sugar, butter, egg yolks, salt and spices in a large bowl. Beat until light and fluffy.

Add evaporated milk. Mix just enough to combine. Beat egg whites in a separate bowl until foamy. Gradually add sugar beating until stiff.

Fold into potato filling. Pour filling into pie. Cook at 400°F for 10min. Reduce heat to 350°F and bake an additional 45 to 50 min or until set. Cool. Top with whip topping.