½ cup all-purpose flour
½ cup quick-cooking rolled oats
½ cup light muscovado sugar
1 teaspoon ground cinnamon
7 tablespoons unsalted butter, cut into small cubes, cold
2 cups graham cracker crumbs
8 tablespoons (1 stick) unsalted butter, melted
⅛ teaspoon ground cinnamon
1 large egg, lightly beaten
3 large eggs
3 large egg yolks
¾ cup dark muscovado sugar
¼ cup granulated sugar
2 tablespoons molasses
1½ cups canned pumpkin puree
1¼ teaspoons ground cinnamon, plus more for the top
1 teaspoon ground ginger
½ teaspoon ground nutmeg
¼ teaspoon ground cloves
½ teaspoon fine salt
1 cup heavy cream
½ cup whole milk
½ vanilla bean, split lengthwise, seeds scraped out and reserved, or 2 teaspoons pure vanilla extract
3 tablespoons unsalted butter, melted
Bourbon-Maple Whipped Cream
1¼ cups heavy cream, very cold
½ vanilla bean, split lengthwise, seeds scraped out and reserved
2 tablespoons Grade B maple syrup
1 to 2 tablespoons bourbon
To make the cinnamon crunch : preheat the oven to 350 degrees F. Combine the flour, oats, muscovado sugar, and cinnamon in a food processor, and process a few times to combine. Add the butter and pulse until combined. Pat the mixture evenly into a 4-inch square on a parchment-lined baking sheet. Bake until golden brown and crisp, about 15 minutes. Remove and let cool. Transfer to a cutting board and chop into small pieces. Keep the oven on.
To make the crust : combine the graham cracker crumbs, butter, and cinnamon in a bowl and mix until combined. Press evenly onto the bottom and sides of a 10-inch pie plate. Brush with the beaten egg. Bake until light golden brown and firm, about 12 minutes. Remove from the oven and let cool on a wire rack.
Reduce the oven temperature to 300 degrees F.
To make the filling: whisk the eggs, egg yolks, both sugars, and the molasses together in a medium bowl. Mix in the pumpkin puree, cinnamon, ginger, nutmeg, cloves, and salt. Whisk in the heavy cream, milk, and vanilla seeds or extract. Strain the mixture through a coarse strainer into a bowl. Whisk in the butter.
Place the pie plate on a baking sheet, pour the pumpkin mixture into the shell, and sprinkle additional cinnamon over the top. Bake until the filling is set around edges but the center still jiggles slightly when shaken, 45 to 60 minutes. Transfer to a wire rack and cool to room temperature, about 2 hours.
Cut the pie into slices and top each with a large dollop of whipped cream and some of the cinnamon crunch.
Bourbon-Maple Whipped Cream : Combine the cream, vanilla seeds, maple syrup, and bourbon, to taste, in a large chilled bowl, and whip until soft peaks form.