Sweet-Potato Custard Pie

On a lightly floured piece of parchment, roll out dough into a 13-inch round, about 1/8 inch thick. Fit into a 9-inch pie dish. Using kitchen shears, trim to a 1-inch overhang; fold under. Crimp edges or decorate as desired. Lightly prick bottom of dough with a fork. Refrigerate 30 minutes.

Preheat oven to 375 degrees with a rack in lower third. Line dough with parchment; fill with dried beans or rice. Bake until edges begin to turn golden, 20 to 25 minutes. Remove beans or rice and parchment; bake until bottom and sides are golden brown, about 20 minutes more. Transfer to a wire rack; let cool completely. (Crust can be made up to a day in advance and covered tightly in foil.)

Increase oven temperature to 400 degrees. Arrange sweet potatoes on a parchment-lined baking sheet and roast until tender when pierced with the tip of a knife, about 1 hour. Remove and let cool slightly; reduce oven temperature to 350 degrees and place a foil-lined baking sheet below rack. When cool enough to handle, peel sweet potatoes, discarding skins. Place flesh in a food processor and process until smooth. (Puree can be made ahead and refrigerated in an airtight container up to 5 days.)

In a bowl, whisk together eggs, sugar, vanilla, cinnamon, nutmeg, and salt until well combined. Whisk in half-and-half. Add 1 1/4 cups sweet-potato puree; whisk until thoroughly combined. Pour mixture into crust (do not overfill). Cover edges with a foil ring, avoiding custard. Place pie dish directly on rack and bake until filling is just set in center, 50 to 55 minutes. Transfer to wire rack; let cool completely, at least 2 hours. Refrigerate, uncovered, until chilled, at least 4 hours or, loosely covered, up to 2 days.

When ready to serve, spray kitchen shears or a knife with oil; cut marshmallows in half crosswise. Shingle on top of pie in concentric circles, cut-sides down. Move a small kitchen blowtorch back and forth across marshmallows until caramelized, or place pie under the broiler until toasted, 10 to 15 seconds.