PUMPKIN LAYER CAKE WITH CARAMEL BUTTERCREAM

Steps:

• Heat oven to 350 degrees. Butter three 8-inch cake pans and line the bottoms with parchment paper. Flour the pans and paper.
• Sift the flour, baking powder and baking soda into a large bowl.
• In the bowl of a stand mixer fitted with the paddle attachment, combine the sugar, butter, spices and salt. Beat on medium-high until very light and fluffy, about 5 minutes. Stop the mixer occasionally to scrape the bottom and sides of the bowl. Add the eggs one at a time, mixing for about 20 seconds between each egg. Add the vanilla extract and pumpkin purée and mix until well combined, scraping the bottom and sides of the bowl as necessary. The mixture will look curdled.
• Set mixer to low, and add the dry ingredients all at once, stirring until a few spots of flour remain. Remove the bowl from the mixer, and use a rubber spatula to finish folding the dry ingredients into the batter. Scrape the bottom and sides of the bowl to ensure the batter is evenly mixed.
• Divide the batter among the prepared pans (about 3 cups per pan), smooth the tops, and tap the pans on a countertop to release any large air bubbles. Bake the cakes until golden and puffed, and a tester inserted into the center comes out clean, 20 to 25 minutes.
• Cool the cakes in the pans on a rack for 10 minutes, then use the tip of a knife to loosen the edges and carefully invert them onto the rack to cool completely.
• Meanwhile, make the caramel sauce: In a large saucepan over medium-high heat, combine the sugar and 3 tablespoons water. Swirl the pan occasionally until the sugar dissolves, but do not stir. Continue to cook, swirling the pan occasionally to help the mixture brown evenly, until it is deep amber in color. At this point, don't walk away from the pot: The caramel will go from amber to burned in mere moments.
• Remove the pan from the heat, and carefully whisk in butter and heavy cream. The mixture will expand and sputter before turning into a smooth sauce. Add the whiskey and salt. Carefully pour the caramel into a heat-safe container and cool to room temperature. You will have about 1 1/2 cups.
• Make the buttercream: In the bowl of a stand mixer, combine the egg whites and sugar. Set the bowl over a pot of simmering water, and whisk continuously until the sugar has dissolved and the mixture is hot to the touch, 5 to 7 minutes.
• Use the whisk attachment of the stand mixer to beat the egg white mixture until stiff, glossy peaks form and the mixture and bowl are cool to the touch, about 10 minutes.
• Switch to the paddle attachment and reduce speed to medium. With the mixer running, add the butter a couple of tablespoons at a time and beat the buttercream until smooth and fluffy. During this step, the buttercream will likely break and look curdled; turn up the speed on the mixer for a few seconds, and it will come back together. Continue until all of the butter is incorporated then add the salt. Slowly add 1/2 cup cooled caramel sauce, and stir until well combined. If the buttercream is extremely soft or runny, put the bowl in the refrigerator for about 10 minutes, then whip until smooth.
• Assemble the cake: If necessary, use a serrated knife to trim the cooled cake layers so they are flat and even. Add a small spoonful of buttercream onto a cardboard cake round or serving plate, and place the first layer of cake, cut side up, on top.
• Spread about 3/4 cup buttercream on top of the cake. Drizzle the buttercream with 1 tablespoon of caramel sauce. Be careful not to drizzle the caramel all of the way to the edge so it doesn't spill out the sides.
• Place the second cake layer on top and repeat with buttercream and caramel. Place the final layer on top, cut side down, and spread the top and sides of the cake with a thin, even layer of buttercream. Refrigerate the cake until the buttercream is firm, about 30 minutes.
• Spread the remaining buttercream in an even layer over the cake. If you'd like to add a caramel drizzle, refrigerate the fully frosted cake until firm then carefully spread about 1/3 cup of room temperature caramel sauce over the top of the cake. Use an offset spatula to gently ease it towards the edges so it drips down the sides. Serve at room temperature. Store leftover cake in the refrigerator, but bring to room temperature before serving. Leftover caramel sauce can be stored in an airtight container in the refrigerator.