Pre-heat oven to 350°F. Grease and flour two 8-inch cake pans and set aside. Sift together the dry ingredients and set aside.
In the bowl of an electric stand mixer fitted with the paddle attachment, mix together the oil, brown sugar and granulated sugar for about 3 minutes. With the mixer on low, add in the eggs, one at a time. Stop the mixer and scrape down the sides and bottom of the bowl.
With the mixer on low, add in the dry ingredients in two additions, mixing well in between. Just as the last streaks of flour begin to disappear, stop the mixer. Add in the pumpkin and mix until combined.
Evenly distribute the batter between the two pans and bake for 30 to 35 minutes or until a toothpick inserted into the center of the cakes comes out clean. Let cool on a wire rack for 10 to 15 minutes before removing the cakes from their pans. Once cool, carefully slice each cake in half horizontally with a serrated knife to create four even layers.
Brown Butter Graham Frosting
Place 1 ½ cups of butter in a light-colored medium saucepan. Over medium-low heat, melt then brown the butter. Turn the heat to medium-high and brown the butter, about 8 minutes. Stir the butter to keep the milk solids from sticking and burning to the bottom of the pan. When done, the butter will be very fragrant and nutty, light-medium amber in color, with dark brown bits at the bottom of the pan. Strain the browned butter with a mesh sieve into a heat-safe container and chill in the refrigerator until it reaches the same consistency as room temperature butter.
Bring the remaining 1 ½ cups butter to room temperature. Place the egg whites and sugar in the bowl of a stand mixer. Gently whisk them by hand to combine. Fill a medium saucepan with a few inches of water and bring to a simmer. Place the mixer bowl on top of the saucepan with create a double-boiler. Whisking intermittently, heat the egg mixture until it reaches 160°F (70°C) on a candy thermometer. Carefully fit the mixer bowl back onto the stand mixer.
With the whisk attachment, beat the egg white mixture on high speed for 8 to 10 minutes, the mixture holds medium-stiff peaks and the outside of the bowl returns to room temperature.
Turn the mixer down to low and add in the vanilla, unsalted butter, and browned butter, a couple tablespoons at a time. Stop the mixer and swap out the whisk for the paddle attachment.
Turn the mixer to medium-high and beat until the buttercream is silky smooth, 3 to 5 minutes. Add the graham cracker crumbs and cinnamon. Mix until combined.
Place one layer of cake on a cake board or serves dish. Spread on about 1 cup of buttercream and smooth with an offset spatula. Top with the next layer of cake and repeat with remaining layers. Frost the cake with the remaining buttercream.
To decorate, pipe dollops of whipped cream and finish with a pie crust cut-out. Serve at room temperature.
For the pie crust cut-outs, simply bake about 375 until puffed and golden (about 8 to 12 minutes). Sprinkle on some cinnamon or freshly grated nutmeg before baking.