01 -  Preheat oven to 400°F. Prick sweet potatoes with a fork, arrange on a baking sheet, and roast for 45–50 minutes until thoroughly tender. Allow to cool, peel, and mash until no lumps remain. Lower oven temperature to 350°F. 
 02 -  In a large mixing bowl, combine mashed sweet potatoes, packed brown sugar, melted butter, whole milk, eggs, white miso paste, vanilla extract, ground cinnamon, ginger, nutmeg, and fine sea salt. Whisk until mixture is homogenous and silky. 
 03 -  Transfer filling into the pie crust, distributing evenly and smoothing the surface with a spatula. 
 04 -  Bake at 350°F for 40–45 minutes or until edges are set and the center quivers gently when shaken; a knife inserted should come out mostly clean. Remove from the oven and position on a wire rack. 
 05 -  Allow pie to cool to room temperature on a wire rack. Refrigerate for a minimum of 2 hours to achieve optimal texture. 
 06 -  In a chilled bowl, whip heavy cream with powdered sugar and vanilla using an electric mixer or whisk until soft peaks form. 
 07 -  Cut pie into slices and serve each portion with whipped cream and toasted pecans if desired.