Step 1

For the Butternut Squash Purée: Adjust oven rack to lower-middle position and preheat to 400°F (205°C). Split the squash lengthways, remove seeds, and place cut-side down on a foil lined aluminum baking sheet. Roast until fork-tender, about 45 minutes. When cool enough to handle, scrape pulp into a food processor and purée until smooth. Measure out 14 ounces (about 1 3/4 cups; 395g) squash purée. Use warm, or refrigerate in an airtight container up to a week in advance.

Step 2

For the Custard: Adjust oven rack to lower-middle position and preheat to 375°F (190°C). In a medium bowl, combine butternut squash purée, homemade condensed milk, brown sugar, vanilla or bourbon, ginger, cinnamon, nutmeg, salt, cloves, butter, and eggs. Whisk until well combined, then pour into the prepared crust. Alternatively, the prepared custard can be refrigerated for up to a week before use.

Step 3

To Bake: Place on a half sheet pan and bake about 25 minutes, then reduce oven temperature to 350°F (175°C) and continue baking until the filling is firm around the edges but still wobbly in the very center, about 25 minutes more, or to an internal temperature of 200°F (93°C).

Step 4

Cool at room temperature until the custard has set, about 2 hours, and cut with a chef's knife to serve. If you like, serve with a dollop of whipped cream and a sprinkling of grated nutmeg. Wrapped in plastic, leftovers will keep 4 days at room temperature, or 10 days in the fridge.