Step 1

Preheat the oven to 350°.

Step 2

Prepare cake mix according to package directions using buttermilk, oil, and eggs. Pour the batter into a prepared 9-by-13-inch baking pan. Bake according to package directions. Cool completely on a wire rack, about 1 hour. Once cool, cut about half of the cake into 1-inch pieces (resulting in 6 cups of cake cubes). Reserve remaining cake for another use.

Step 3

Place the cream cheese in a large bowl and beat with an electric mixer on medium speed until smooth and creamy, about 1 minute. Add the pumpkin puree, 1 cup of the sugar, pumpkin pie spice, and 1 tsp. vanilla extract, and beat until fully combined, stopping to scrape the sides of the bowl as needed.

Step 4

With a clean bowl and beaters, beat the heavy cream, remaining 1/2 cup sugar, and remaining 2 teaspoons vanilla extract with an electric mixer at medium-high speed until stiff peaks form, about 1 1/2 minutes. Gently fold 1 1/2 cups of the whipped cream into the pumpkin mixture.

Step 5

Arrange half of the cake pieces (3 cups) in the bottom of a large trifle dish. Spread half of the pumpkin mixture on top of the cake. Sprinkle half of the crushed cookies on top of the pumpkin. Spread half of the whipped cream on top of the crumb mixture. Repeat layers, topping with candied ginger and additional cookies crumbs. Serve immediately, or cover and chill for up to 1 day before serving.