COOK sweet potatoes in boiling water for 45 to 50 minutes or until tender. Drain, cool slightly and peel.
PREHEAT oven to 425° F.
MASH warm sweet potatoes and butter in large bowl. Stir in granulated sugar, evaporated milk, eggs and brown sugar. Stir in lemon juice, vanilla extract, cinnamon, nutmeg and salt. Pour into pie shells.
BAKE for 15 minutes. Reduce heat to 350° F; bake for 30 to 40 minutes or until knife inserted near center comes out clean. Cool on wire rack for 2 hours. Top with whipped cream. Serve immediately or refrigerate.