Place squash in a steamer basket over 1 inch of boiling salted water in a large pan for 12 to 15 minutes, until tender. Puree in a food processor until smooth. Measure 1 1/2 cups puree for pie; cover and refrigerate any remainder for another use.
Prepare pie crust; press into 9-inch pie dish.
Preheat oven to 350°F. Line a rimmed baking sheet with foil. Place pie dish on baking sheet.
In a medium bowl, whisk together eggs, molasses, sugar, milk, cinnamon, cloves, salt and pepper until smooth. Whisk in squash puree until combined. Pour filling evenly into pie crust.
Bake pie until filling is set and slightly puffed in the center, 45 to 55 minutes. Let pie cool completely on a wire rack. Serve with whipped cream, if desired.