Preparation

1. 1. Prepare the cake: Fit the oven with the rack in Position 1.Coat a 9-inch round cake pan with softened butter or nonstick cooking spray; reserve.
2. 2. Put the flour, cocoa powder, espresso powder, baking soda, baking powder and salt into a large mixing bowl.Whisk to combine; reserve.
3. 3. Put butter and sugars into a large mixing bowl.Using a hand or stand mixer, mix the butter and sugars together until light and creamy.On a low speed, slowly add the egg, yolk and vanilla extract.Scrape down as necessary.
4. 4. Add
5. 1/3 of the dry ingredients and, while mixing on low, add ½of the buttermilk.While still mixing on low, gradually add an additional 1/3 of the dry ingredients and then the rest of the buttermilk.Finish with the remaining dry ingredients and gently mix until combined.
6. 5. Transfer the batter to the prepared cake pan.
7. 6.
8. Set to Bake at 350°F for about 20 minutes.After 5 minutes, transfer the cake to the preheated oven.Bake until cake springs back to the touch, about 15 minutes.Remove from oven and allow to fully cool.Once room temperature, transfer to a refrigerator to chill.
9. 7. Prepare the frosting: Using a hand or stand mixer, mix 2 sticks of the butter, confectioners’ sugar and salt until light and creamy.Add the vanilla extract and 2 tablespoons of the cream and continue to mix until fluffy.Reserve.
10. 8. Put the granulated sugar with enough water to just cover (should resemble wet sand) in a heavy-bottomed medium saucepan.Set over medium heat and allow to cook until sugar is the color of light maple syrup.As soon as the sugar achieves that color, remove from heat and very carefully whisk in the remaining 2 tablespoons of butter andcream.Cool to room temperature.
11. 9. Once cool, mix 3 tablespoons of the caramel sauce into the frosting; reserve the remaining tablespoon for finishing the cake.
12. 10. Once the cake is sufficiently cooled, remove from the refrigerator and halve to make two even layers.Put one onto a cake stand or plate and top with half of the frosting.Place the second layer on top and finish with the remainder of the frosting.Decorate as desired and drizzle with the reserved caramel sauce and a pinch of flaked sea salt, if desired.