Chocolate Espresso Cake:
- Preheat oven to 350 F degrees. Grease and flour 2 8in cake pans.
- In a medium sauce pan, melt the butter. Add the coffee, espresso powder, cocoa powder, and vanilla and whisk until combined. Set aside to cool slightly.
- In a large bowl, sift together the sugar, flour, baking soda and salt. Set aside.
- In a medium bowl, whisk together the sour cream and the eggs. SLOWLY add a few tablespoons of the chocolate mixture to the sour cream and eggs. Whisk to combine. In a slow stream, whisk in the remaining chocolate mixture until combined completely.
- Make a well in the center of the flour mixture and pour in wet. Using a whisk, stir until no more lumps remain.
- Divide the batter evenly into the prepared pans. Each pan should get half of the batter.
Bake 23-25 minutes or until a toothpick comes out clean. Cool in pan for 10 minutes before removing from the pans to cool on a wire rack.
- Once the cakes have cooled, but are still warm, using a cake leveler to cut off the round mound on the top of the cake. Make sure all four layers are the same size.
- In a large pan, melt the butter.
- Add the raspberries, sugar and lime and bring to a simmer over medium-high heat. Stir continuously so that the raspberries begin to break down.
- Add the corn starch and stir to combine. Continue to cook until the raspberries thicken, about 2 minutes.
- Stir in the salt.
- Remove from heat and allow to cool completely before filling cake.
Whipped Vanilla Buttercream:
- In the bowl of your stand mixer, cream the butter until smooth.
- One cup at a time, add the powdered sugar and mix until smooth.
- Mix in the vanilla extract and pinch of salt.
- Add enough heavy cream until you reach your desired consistency. You're looking for light and soft but still holds its shape.
- Mix on high for about 3-5 minute until light and fluffy.
- Place one layer of cake on a cake stand/board. Trim the top until it is flat.
- Pipe a small border of frosting around the outside edge of the cake. Fill the middle with the raspberry mixture.
- Trip the top of the second cake layer until flat. Gently press it trimmed side down onto the raspberry layer.
- Pipe or spread the remaining frosting onto the outside edge of the cake and smooth out with a spatula.
- Decorate as desired.