Tiramisù Layer Cake With Mascarpone Mousse

• portions: 12 servings

Ingrédients

¾ cup (190 g) sweet Marsala

½ cup plus 2 Tbsp. (150 g) brewed espresso, cooled

1½ tsp. unflavored powdered gelatin

1 cup (224 g) heavy cream

4 (59 g) large egg yolks, room temperature

2 Tbsp. (26 g) sweet Marsala

2 Tbsp. (26 g) granulated sugar

1 tsp. vanilla extract

½ tsp. kosher salt

8 oz. (227 g) mascarpone

Vanilla Genoise

Espresso Swiss Meringue Buttercream

Instructions

Combine Marsala and espresso in a small bowl. Cover and chill.

Do Ahead: Soak can be made 3 days ahead. Keep chilled.

Place ¼ cup cold water in a small bowl and sprinkle gelatin evenly over top; chill until ready to use.

Beat cream in the bowl of a stand mixer fitted with the whisk attachment on medium-high speed until medium peaks form. Scrape whipped cream into a medium bowl; cover and chill. Reserve bowl; you don’t need to clean it.

Whisk egg yolks, Marsala, sugar, vanilla, and salt in a medium heatproof bowl until smooth; set over a saucepan of just barely simmering water (do not let bowl touch water). Heat, whisking constantly, until yolks are lightened in color and doubled in volume, about 5 minutes. Mixture should feel warm to the touch. Remove egg yolk mixture from heat and scrape into reserved bowl. Fit bowl onto mixer.

Remove saucepan from heat and pour out water, then scrape in softened gelatin. Heat over medium-low, swirling pan often, until gelatin is dissolved, about 1 minute. With mixer on medium speed, stream gelatin into egg yolk mixture. Beat until sides of bowl are cool to the touch, about 2 minutes; add mascarpone and beat until smooth.

Remove bowl from mixer and gently fold in chilled whipped cream. You should have about 4 cups mousse. Cover with plastic wrap, pressing directly onto surface; chill until set, at least 4 hours.

Do Ahead: Mousse can be made 3 days ahead. Keep chilled.

Line a 9"-diameter cake pan or springform pan with plastic wrap, pressing into bottom and leaving generous overhang. Fit a 1-piece round of cake into pan, placing bottom side up. Using a pastry brush, dab a quarter of soak across entire surface of cake. Stir chilled mousse to loosen, then scrape a third over cake and smooth into an even layer with a small offset spatula. Place another round of cake, bottom side up, on top of mousse, this time using a 2-piece layer. Repeat soaking and filling process. Top with the remaining 2-piece round of cake, bottom side up, and repeat soaking and filling process one more time. Top with remaining 1-piece round of cake, bottom side up, and brush with remaining soak. You should have 4 layers of soaked cake separated by 3 layers of filling. Wrap plastic overhang up and over cake; chill at least 12 hours and up to 2 days to allow mousse to set and cake to absorb soak.

To frost, remove plastic from top of cake and invert cake onto a cake plate or platter. Remove pan and plastic. Dollop about 1 cup buttercream over top of cake and smooth across top and down sides, creating a very thin base layer. You want to fill in any gaps, adhere any crumbs to the cake, and seal in the fillings (this is called a crumb coat). Chill cake 10 minutes, then scrape remaining frosting on top of cake and spread all over, working down and around sides. Decorate as desired.

Do Ahead: Cake can be made 2 days ahead. Chill until frosting sets, then cover loosely with plastic wrap. Let sit at room temperature 1–1½ hours before slicing.

Highly recommended reading: Layer cake tips, tricks, and common mistakes from Natasha Pickowicz.