Sweet Potato Pie with Marshmallow Meringue

INGREDIENTS

• 1/2 (14.1-oz.) package refrigerated piecrusts
• Parchment paper
• 1 egg yolk, lightly beaten
• 1 tablespoon whipping cream
• 1/4 cup butter, melted
• 1 cup sugar
• 1/4 teaspoon salt
• 3 large eggs
• 3 cups lightly packed, cooked, mashed sweet potatoes (about 2 1/2 lb. sweet potatoes)
• 1 cup half-and-half
• 1 tablespoon lemon zest
• 3 tablespoons lemon juice
• 1/4 teaspoon ground nutmeg
• 3 egg whites
• 1/2 teaspoon vanilla extract
• 1/8 teaspoon salt
• 1/4 cup sugar
• 1 (7-oz.) jar marshmallow crème