Pumpkin Meringue Pie Ice Cream

In a medium bowl, whisk together the 5 large egg yolks, 1/2 teaspoon ground cinnamon, 1/2 teaspoon freshly grated nutmeg, 1/2 teaspoon ground ginger, 1/4 teaspoon ground mace, and large pinch of salt until smooth.
In a medium pan, add the 2 cups heavy cream and 1 cup firmly packed dark brown sugar. Whisk to combine.
Heat the cream-sugar mixture over medium heat, stirring frequently, until the sugar dissolves, ⏲ 3 to 5 minutes. Don't allow the liquid to boil!
While whisking the yolks, slowly drizzle the hot cream-sugar mixture into the bowl. Return the cream-yolk mixture back to the saucepan.
Place the saucepan over medium heat and cook, whisking constantly, until the custard is thick enough to coat the back of a spoon. Swipe a line across the spoon with your finger—if it holds, it’s done, ⏲ 5 to 8 minutes. Alternatively, if you have a thermometer, cook the custard until it reaches 185°F (85°C).
Strain the hot custard through a sieve into a clean bowl. Gently stir in the 1 cup canned unsweetened pumpkin purée 2 teaspoons vanilla extract, and 1 1/2 tablespoons spiced rum or bourbon, if using.
Lightly coat a piece of plastic wrap with cooking spray and press it against the surface of the custard. Refrigerate for at least ⏲ 3 hours and up to 24 hours.

Line a rimmed baking sheet with foil and lightly coat with cooking spray. Crank up the oven to 350°F (180°C).
In a food processor, finely grind the 8 Oreos. Dump the crumbs into a small bowl, add the 2 tablespoons melted butter, and mix until combined.
Dump the crumbs onto the foil-lined baking sheet and pat them into a 1/8-inch (3-mm) thick slab. Bake until the surface looks dry, ⏲ 10 to 15 minutes. Transfer the sheet to a rack and cool completely. Break up into bite-size pieces.

Pour the fully chilled custard into a 1-quart-capacity ice cream maker and churn according to the manufacturer’s direction until the custard is thick and is the texture of soft serve.
☞ TESTER TIP: Due to the addition of booze, the ice cream will take longer to reach soft-serve stage, but fear not!

Spoon the 1/2 cup jarred marshmallow spread into a small microwave-safe bowl and nuke in 5-second bursts until the spread softens, about 15 seconds total. Vigorously stir the spread with a spoon to release the air making the spread smooth and lightly pourable.
Spread 1/3 of the ice cream into the bottom of a plastic freezer container. Spoon half of the marshmallow over the ice cream and use a knife to quickly marble it through the ice cream. Stick half of the crust shards into the ice cream. Repeat with another layer of ice cream, marshmallow, and shards. Top with the remaining third of ice cream and spread it smooth.
Cover tightly, and freeze until firm, at least 3 hours or overnight (8 to 12 hours). Let soften for 10 minutes at room temperature before serving.