Butternut squash gives this pie a rich, buttery taste, but you can use pumpkin instead; substitute 1 2/3 cups canned pumpkin puree and skip step 1.
Preheat oven to 350 degrees, with rack in center. Place squash in a medium saucepan, and add enough water to cover. Bring to a boil over high heat; reduce to a simmer, and cook until the tip of a paring knife easily pierces squash, 20 to 25 minutes. Drain, and set aside to cool.
Transfer squash to a food processor. Add half-and-half, brown sugar, cinnamon, nutmeg, and salt; puree until smooth, scraping down sides of bowl as needed. Add eggs, and pulse until combined.
Place pie crust (in pie pan) on a baking sheet. Pour filling into crust. Bake, rotating once halfway through, until filling is set, 50 minutes to 1 hour (tent loosely with foil if edges are browning too quickly).
Cool completely. Serve with whipped cream, if desired.
To prepare the squash: Halve squash lengthwise, peel with a vegetable peeler or paring knife, and then scoop out seeds with a spoon.