• Preheat oven to 350°F. Spray two 9-inch cake pans with GOOP (see notes) or parchment or baking spray.

Cake

• Sift cake flour, baking powder, and salt together in a large bowl. Set aside.
• In stand mixer fitted with paddle attachment, beat egg whites on high speed until soft peaks form, about 2- 3 minutes. Set aside.
• In your wiped out stand mixer bowl and still using paddle attachment, beat butter on high for 1 minute, or until smooth and creamy. Add the sugar and beat on high for 3-4 minutes. Scrape bowl as needed.
• With mixer on low, add egg yolks and vanilla. Then beat on medium-high until combined.
• With mixer on low speed, add in dry ingredients, scraping bowl as needed, in 3 additions alternating with milk. Mix until everything is just combined, do not overmix.
• Remove bowl from stand mixer and using a rubber spatula, fold in egg whites.
• Pour batter into prepared pans. Bake for 25-28 minutes or until an inserted toothpick comes out clean.
• Remove cakes from oven and allow to cool completely in the pans on a wire rack.

Caramel Sauce

• Combine the brown sugar, heavy cream, butter, and salt in a medium-size saucepan over medium heat. Stir constantly with a wooden spoon (not rubber) until butter is melted, about 2-3 minutes.
• Bring to a boil and, without stirring, allow to boil for 3 minutes.
• Remove saucepan from the heat and stir in the vanilla extract.
• Allow to cool for 15 minutes, then pour into a glass jar and cover tightly. Allow to cool to room temperature, about 45 minutes, or in the refrigerator, about 30 minutes, before using on the cake.

Chocolate Frosting

• In a stand mixer fitted with paddle attachment, beat the butter on medium speed until creamy, about 2 minutes.
• Add in 3 ½ cups confectioners' sugar, cocoa powder, salt, vanilla, and ¼ cup (60ml) heavy cream with the mixer running on low.
• Once incorporated increase speed to high and beat for 3 minutes.
• If the frosting is too thin, add in 2 tablespoons confectioners' sugar or add 1 tablespoon heavy cream if it is too thick.
• Taste the frosting; add in extra pinch of salt if frosting is too sweet.
• Measure 1 cup of frosting and place it in a separate bowl. Fold in ½ cup (80 g) of the chopped candy bars into the 1 cup of frosting. Set aside.

To Assemble

• Level cakes to create a flat surface.
• Place 1 layer of cake on cake-stand or serving plate. Evenly spread frosting-candy bar mixture over top.
• Be gentle and this is a thick mixture and your cake is fragile.
• Top with second cake and spread the plain frosting all over top and sides.
• SALLY'S CAKE FROM HER BOOK: Decorate top with a few chopped candy bars and drizzle with caramel.
• MY CAKE: Press remaining chopped candy bar into sides of cake. Simply scoop chopped candy bars bits into palm of your hand then press into the side of the cake. After cake has been covered you can use a fondant smoother or baker's blade to press into the sides to create an even surface.
• Place any remaining bits on top of cake and the drizzle with caramel sauce.
• Cover any leftover cake tightly and store at room temperature for up to 3 days or in the refrigerator for up to 5 days.