Prepare 2-8” or 9” round cake pans by spraying with panspray and lining the bottom of each with parchment paper.
Sift dry ingredients together.
In the bowl of a stand mixer fitted with a whisk attachment,or in a large bowl with a handheld mixer, mix eggs, milk, vanilla and brown sugar for 3-5 minutes on medium speed until combined and slightly bubbly.
Add dry ingredients to egg mixture and mix until just combined. Add hot coffee and mix until combined.
Divide batter between the two prepared pans and bake for25-30 minutes. Cakes are done when a toothpick inserted into the center comes out with a few moist crumbs attached.
Cool cakes in pan for 10 minutes and then unmold onto a wire rack and remove parchment paper. Let cool completely. Slice each cake in half lengthwise to produce four cake layers. Wrap layers in plastic and set aside until ready to use. Cake can be made up to a day in advance and kept in the refrigerator.
In a small microwave-safe bowl, melt chocolate in the microwave in 20 second intervals. Stir between each interval until melted. Mixin about a ¼ of the sweetened condensed milk. Set aside to cool.
In the bowl of a stand mixer fitted with the whisk attachment, or in a large bowl with a handheld mixer, whisk butter for 5 minutes on high speed. Stop the mixer periodically to scrape down the sides and bottom of the bowl. The butter is ready when the volume has doubled and is nearly white in color.
With the mixer running, very slowly pour in remaining ¾ of sweetened condensed milk. This should take at least one minute. Stop mixer to scrape sides and bottom of bowl. Add chocolate mixture and continue to whip for 2 more minutes. Cover and set aside until ready to use. Buttercream can be made up to two days in advance and kept at room temperature. Beat lightly before using.
Peanut Butter Caramel
In a medium saucepan, add water and sugar. Let sugar caramelize over medium heat without stirring.
Once caramel is at a medium amber color, remove pan from heat and slowly add cream in 4-5 additions, carefully stirring between each addition. Caramel will bubble up and the steam will be very hot.
Add salt and peanut butter. Return to medium heat and cook 2-3 minutes more.
Pour caramel into a heat proof bowl, cover surface of caramel with plastic wrap and set aside to cool. Caramel can be made up to two days in advance and kept at room temperature.
Peanut butter Popcorn
In the bowl of a food processor, pulse caramel corn and peanuts until mostly chopped. There will be some large pieces and small pieces. Alternately, chop popcorn and peanuts on a cutting board.
Transfer to a large bowl. In a microwave safe bowl, melt chocolate, butter, peanut butter and salt in the microwave in 30 second intervals. Stir between each interval until melted.
Pour chocolate mixture over popcorn mixture and stir to combine. Evenly spread mixture onto a parchment lined baking sheet and let cool. Set aside until ready to use. Crunch can be made up to a day in advance kept in an airtight container at room temperature.
Place egg whites and salt in the bowl of a stand mixer fitted with a whisk attachment, but do not turn on yet.
In a medium saucepan with a thermometer, combine water, sugar and honey and bring to a boil. Continue boiling until syrup reaches 239°F/115°C.
Continue to boil syrup and begin whisking egg whites and salt on medium-high speed to bring to soft peaks.
Once sugar syrup reaches 245°F/118°C, remove pan from heat and with the mixer running, slowly pour syrup into mixing bowl in a steady stream aiming for the side of the bowl just above the egg whites. Be careful to not let the syrup hit the whisk as it may splatter.
Turn mixer to high speed and whisk until nougat has tripled in volume and is still slightly warm. Use mixture immediately in assembly of cake.
Place buttercream in a pastry bag fitted with a ½” round tip.
Place first layer of chocolate cake on a plate, cake stand or cake turntable.
Pipe a border of buttercream around the top edge of the first layer. Fill in border with a small amount of caramel (about 1/3 of caramel) and spread from the middle of the cake to the edge of the butter cream.
Sprinkle about ½ cup of popcorn crunch on top of caramel. Top caramel with about half of nougat mixture and, being careful to not go above the edge of the buttercream border evenly spread.
Place another layer of cake on top. Repeat process of piping a border of buttercream and fill in with more buttercream for this layer.
Place another layer of cake on top and repeat process of first layer of filling (buttercream border, caramel, crunchand nougat).
Place final layer of cake on top.
Frost top and sides of cake with remaining buttercream scraping sides to reveal chocolate cake underneath.
Place cake in the refrigerator to firm up (about 1 hour). Once firm, remove cake from refrigerator.
In a heat-proof bowl, microwave remaining peanut butter caramel with 1-2 tablespoons of heavy cream for a few seconds until barely warm, but not hot. Mixture should be thick, but pourable. Slowly pour caramel to cover the top of the cake and around the edge of cake letting some of caramel drip down the sides. Allow caramel to set up before slicing cake.
Cake can be assembled up to a day in advance kept in the refrigerator. Cake can be served coldor allowed to come to room temperature.