One 8-ounce package cream cheese, at room temperature
One 15-ounce can pumpkin puree
8tbsp.(1 stick) unsalted butter, melted
1½ teaspoons pure vanilla extract
One 1-pound box (4 cups) confectioners’ sugar
½ teaspoon ground mace
1tsp.freshly grated nutmeg
Position a rack in the middle of the oven and preheat the oven to 350℉. Grease a 9-by-13-by-2-inch baking pan and line with parchment, allowing the paper to hang over the edges.
To make the crust: put the butter in a large heatproof bowl, set it over a pot of barely simmering water, and stir frequently until melted. Remove from the heat and stir in the sugar, vanilla, and salt. Add the flour all at once and mix until just incorporated.
Press the dough evenly into the bottom of the prepared pan. Bake for 20-25 minutes, until golden on the edges but still light brown in the center. Let the crust cool for at least 30 minutes.
In the bowl of a stand mixer fitted with the paddle attachment (or in a medium mixing bowl, using a handheld mixer), beat the cream cheese on medium speed until smooth and creamy, 5 to 7 minutes. Add the pumpkin and mix until thoroughly incorporated, about 5 minutes. Turn the speed to low, add the melted butter and vanilla, and mix until combined, 2 to 3 minutes. Add the confectioners’ sugar, mace, cinnamon, nutmeg, and eggs, beating until all the ingredients are thoroughly combined. Continue to mix on medium speed until smooth, about 5 minutes.
Pour into the prepared crust. Bake for 50 minutes to 1 hour, until the center is firm. Let cool to room temperature, then refrigerate.
Cut the bars into squares and serve chilled with the whipped cream, if desired. The bars will keep in an airtight container in the refrigerator for up to 3 days.