the goods:
crunch topping:
3 cups walnuts
3 cups mini Nilla wafers
3 cups brown sugar
1 cup (2 sticks) butter, melted
pumpkin cake:
1 and 1/4 cup sugar
3/4 cup (1 and 1/2 sticks) butter, room temperature
1 can (16 oz.) pumpkin puree
2 and 1/2 cups flour
1/2 cup sour cream
1 tablespoon vanilla extract
1 tablespoon pumpkin pie spice
2 and 1/4 teaspoons baking powder
3/4 teaspoon baking soda
1/2 teaspoon salt
4 eggs
frosting:
2 blocks (16 ounces) cream cheese, room temperature
8 ounces marscapone cheese
1 cup (2 sticks) butter, room temperature
2 cups confectioners' sugar
1 tablespoon vanilla extract
Make the crunch topping: In a food processor, pulse cookies to a fine crumb. Add walnuts and pulse to a fine chop. Add in brown sugar and mix well. Add in melted butter and blend together. Divide mixture into four 9-inch cake pans (1 very full cup per pan), reserving about 1 cup for the top of the cake. Press it into the bottoms of the pans in an even layer (I use the bottom of a glass or measuring cup).
Preheat oven to 350 degrees.
Make cake: In a stand mixer, beat sugar and butter for about 5 minutes until light and fluffy, scraping down the bowl a few times as needed. Add in pumpkin, flour, sour cream, vanilla, pumpkin pie spice, baking powder, baking, soda, and salt. Mix just until blended. Add in eggs, one at a time, just until blended. Divide batter equally into your 4 prepared pans, smooth it out and make it as level as possible. Bake for 25-30 minutes, until a toothpick inserted in the center comes out clean. Put remaining crunch in a baking pan and bake for about 10 minutes. Allow cakes to cool for 10 minutes, then turn them out onto wire racks to cool completely. Break up extra crunch mix into small bits to decorate cake with.
Make the frosting: Whip cream cheese, marscapone, and butter until very smooth and creamy. Slowly add in the sugar while mixer is on low. Add in vanilla and mix well.
Assemble the cake: Place your first layer crunch-side-up on a serving plate. Spread a generous amount of frosting to cover entire surface. Place second layer crunch-side-up and repeat until all layers are stacked. Put remaining frosting on top and sprinkle with broken up crunch. Refrigerate any uneaten (if there is any) cake.