1 1/4sticksunsalted butter 145g, softened but still cool
1/4cupsour cream57g
For the Swiss Meringue Buttercream:
5egg whites room temperature
1 ½cupgranulated sugar300g
1pinchsea salt
1 ¾cupunsalted butter395g, room temperature
1tspvanilla extract5mL
1tbsp Instant Espresso15mL
3tbsp Brandy45mL
For the Syrup:
1cupstrong coffee236g (Espresso Preferred)
1/3cupbrandy79mL
2tbspcoffee liqueur30mL
For the Filling:
1/3cupsugar68g
1/3cupmilk79mL, whole
16ouncemascarpone cheese450g, room temperature
3egg yolks
Instructions
INSTRUCTIONS:
For the Cake:
Preheat oven to 350 degrees. Prepare a cupcakes pan.
Milk and eggs should be kept at room temperature.
In a large bowl, mix the milk, sour cream, egg whites, and extracts. Use a fork until even throughout.
In an electric mixer combine the sugar, baking powder, flour and salt. Mix at a slow speed. Add the butter -- in cubes -- slowly. Continue on low for an additional 2 minutes.
Put 1/2 cup of the milk mixture to the side. Add the rest to the flour mixture.
On medium speed setting, beat for 1.5 minutes. Add the 1/2 cup and beat for an additional 1 minute.
Evenly distribute the batter into cupcake pan.
Bake for 20 minutes or until a toothpick inserted comes out clean. Let cupcakes cool.
For the Filling:
In a heatproof bowl -- over a saucepan of simmering water -- whisk the yolks and sugar. Continue until the sugar dissolves. Whisk in the milk slowly.
Whisk consistently until the combined ingredients have a light/airy consistency (around 10 minutes).
The internal temperature of the mixture should register at 170 degrees when you finish.
Remove bowl from saucepan. Set bowl in ice water. Whisk the mixture until it has cooled (around 1 minute).
Place mascarpone cheese in a large bowl. Fold the mixture into the cheese, using a rubber spatula.
Whisk until it is ALMOST COMBINED completely. Word of caution: do not over mix or it will have a grainy consistency.
For the Swiss Meringue Buttercream:
Add egg whites, sugar and salt in a bowl.
Give the mixture a brief whisk.
Place the bowl over a pan of simmering water. Make sure the water does not touch the bowl.
Whisk the egg whites occasionally while it warms up. When the mixture has warmed, whisk it constantly. You will heat the mixture until it reaches an internal temperature of 160 degrees.
Transfer the bowl to a stand mixer with a paddle attachment.
While the mixture is running on low, add tablespoon sized dollops of room temperature butter making sure to let the butter incorporate before you add the next piece. Mix in your 1 tbsp Instant Espresso (dissolved into 3 tbsp of Brandy, used to flavor the buttercream).
For the Syrup:
You can transfer it to a piping bag or to a ziplock bag to store in the freezer for later. (When you're ready to use it, take it out of the freezer, bring to room temperature, transfer to a bowl and beat it for about 10 second to bring back the consistency).
For the Assembly:
Transfer cooled, mascarpone custard to a piping bag.
Core cupcakes with a corer or scoop out the center with a small knife.
Drizzle the coffee mixture into cupcake hole.
Pipe the mascarpone filling into inside.
Pipe dollops of Swiss Buttercream on the top, using an 869 Tip. Dust tops with cocoa powder and top with a chocolate covered espresso bean.
Video
Notes
WHAT IF YOU CAN’T FIND MASCARPONE ANYWHERE?!?
A while back I was making a cake with a mascarpone buttercream and realized mine had expired! I didn’t have time to go to the market so I followed Nigella’s advice for a reasonable facsimile and mixed the following ingredients together until combined. Make sure they are all at room temperature!8oz cream cheese1/4 cup heavy cream2 tbs unsalted butterCake batter recipe adapted from I Am Baker