Instructions

For Cakes:

1. Heat oven to 350 degrees F. Butter and flour three 8-inch round cake pans. Line with parchment and grease parchment.
2. In a medium bowl, whisk together flour, baking powder, baking soda, and salt.
3. In a small cup, combine the boiling water and espresso. Let cool while you continue.
4. In the bowl of an electric mixer, beat butter and sugars on medium speed until light and fluffy, about 3-5 minutes. Add in eggs, one at a time, and mix until combined. Scrape down the sides of the bowl as needed. Combine the espresso mixture with milk. Alternatively add the flour mixture and espresso-milk mixture to the batter, starting and ending with flour and beating well after each addition.
5. Divide the batter into the prepared baking pans. Bake cakes until the center springs back when touched and a tester comes out clean, about 30-35 minutes. Let cakes cool in pan for at least 10 minutes before turning out onto a cooling rack. Let cool completely before frosting.

To make caramel sauce:

1. In a medium saucepan, melt sugar over medium high heat. When sugar starts melting, whisk until all the sugar melts. Sugar will clump in whisk but keep whisking.
2. Once all the sugar is melted, stop whisking and let sugar get to a deep amber color. You can swirl the pan to mix. Keep your eye on the caramel, as it will easily burn at this stage.
3. Whisk in the butter and mix until completely melted. Remove pan from heat and gradually add in the heavy cream. Whisk until smooth.
4. Transfer caramel immediately into a glass jar and let cool.

For Caramel Swiss Meringue Buttercream:

1. Whisk together sugar and egg whites in a heatproof mixing bowl set over (not in) a pan of simmering water. Whisk until warm and sugar is dissolved (mixture should feel completely smooth when rubbed between your fingers), 2 to 3 minutes. Remove from heat.
2. With an electric mixer on medium speed, whisk egg white mixture 5 minutes (using the whisk attachment). Increase speed to medium-high, and whisk until stiff, glossy peaks form and meringue has cooled (test by feeling bottom of bowl), about 6 minutes.
3. Reduce speed to medium and switch to the paddle attachment. Add butter, one piece at a time, beating well after each addition. Keep beating until the buttercream comes together (IT WILL). Beat in vanilla and coffee extract and caramel until smooth and silky.
4. Use immediately or store in an airtight container in fridge for up to a week.

Assembly:

1. Place one layer of cake on a cake stand or serving platter. Spread about ½ cup of frosting over the top using an offset spatula. Top with another layer of cake and repeat with another layer of frosting. Smooth with offset spatula. Top with final layer of cake.
2. Frost cake with a crumb coat of buttercream and refrigerate for at least 30 minutes. Finish frosting cake and decorate as desired.