01 - Preheat oven to 400°F. Prick sweet potatoes with a fork, arrange on a baking sheet, and roast for 45 to 50 minutes until thoroughly tender. Allow to cool before peeling and mashing until smooth. Reduce oven temperature to 350°F.
02 - In a large bowl, whisk together mashed sweet potatoes, light brown sugar, melted butter, whole milk, eggs, white miso paste, vanilla extract, cinnamon, ginger, nutmeg, and sea salt until fully blended and smooth.
03 - Transfer the prepared filling into the unbaked pie crust. Spread filling evenly to achieve a level surface.
04 - Place pie in oven at 350°F and bake for 40 to 45 minutes. The filling should be just set, and a knife inserted near the center should come out mostly clean.
05 - Set baked pie on a wire rack to cool to room temperature. Once cooled, refrigerate for a minimum of 2 hours prior to serving.
06 - In a mixing bowl, whip heavy cream with powdered sugar and vanilla extract using an electric mixer or whisk until soft peaks form. Serve each slice with whipped cream and garnish with toasted pecans, if desired.