- Preheat oven to 400 degrees
- Beat the egg yolks with an electric hand mixer in a large bowl until light, about 3−4 minutes. Beat in the sweet potatoes. Measure the brown sugar, butter, cinnamon, nutmeg, cloves, ginger, and salt onto a piece of parchment or waxed paper and thoroughly mix. Beat them into the egg mixture until light, about 3−4 minutes. Add the cream and beat until just combined.
- Whisk the egg whites in a clean bowl until they form soft peaks, about 2 minutes. Fold a dollop of the egg white into the potato mixture to soften and then fold the potato mixture into the egg whites.
- Place the prebaked piecrust on a rimmed baking sheet. Pour the filling into the piecrust. Bake for 10 minutes; then reduce the heat to 350 degrees and continue baking for an additional 45 to 50 minutes until a fork lightly inserted in the center of the pie comes out clean. Cover the edges of the crust with foil if browning too quickly. Cool the pie in the pan on a wire rack.
- For topping, whip cream and sugar until it reaches a consistency you like. Stir in vanilla. Serve pie with whipped cream.