9 ounces graham cracker crumbs
1/3 cup plus 2 tablespoon plus 3/4 cup granulated sugar
3 tablespoon Dutch cocoa powder
3/4 teaspoon ground cinnamon, plus 1 tablespoon for sifting
1/4 teaspoon ground nutmeg plus pinch
3/4 cup unsalted butter, melted
1/4 cup brandy
2 tablespoon unflavored gelatin
3 large eggs, room temperature
1-1/2 cups cups canned pumpkin puree
1/4 teaspoon ground allspice
1/4 teaspoon ground ginger
1/2 teaspoon salt
1/4 cup sour cream
1-1/2 cups heavy cream
2 tablespoon confectioners sugar
1/2 teaspoon pure vanilla extract
Heat oven to 325 deg. F. In a food processor, combine graham cracker crumbs, 1/3 cup plus 2 tablespoon granulated sugar, cocoa powder, 1/4 teaspoon cinnamon, and pinch nutmeg; process until finely ground. Transfer to medium bowl; mix in butter. Press mixture onto bottom and sides of 10-1/2 inch tart pan. Bake until set, 12 to 15 minutes. Set aside until cool.
In small bowl, place brandy and 2 tablespoon water. Sprinkle gelatin over liquid; set aside to soften, 10 minutes. In bowl of electric mixer with whisk attachment, beat eggs on medium low speed until fluffy. While mixer is running, combine remaining 3/4 cup sugar and 1/4 cup water in small saucepan over medium-high heat. Cook, stirring occasionally, until temperature registers 245 deg. F. (firm ball stage) on a candy thermometer, about 5 minutes. Immediately turn mixture into running mixer in a thin stream; continue to beat until mixture increases in volume and is pale yellow, about 5 minutes. Meanwhile, place bowl with softened gelatin over saucepan of simmering water; stir until gelatin has dissolved.
Turn mixer to low; add gelatin mixture. Add pumpkin puree, 1/2 teaspoon cinnamon, 1/4 teaspoon nutmeg, allspice, ginger, salt, and sour cream; combine. Pour filling into pie crust; refrigerate until set, 4 hours or overnight.
To serve, whisk heavy cream, confectioners sugar, and vanilla in a medium bowl until stiff. Using and Ateco #864 star tip, pipe whipped cream in rosettes onto pie. Sift remaining TBSP cinnamon on top.