In search of a showstopping cake with a unique combination of flavors, we fell in love with this blackberry-mascarpone lemon cake. It is strikingly beautiful, impressively tall, and features layers of contrasting flavors and textures: tart lemon, sweet blackberries, and a silky rich mascarpone whipped cream. Together, these elements make for a cake that’s both light and decadent. Lemon chiffon cake was the perfect base; it has a light fluffy texture but enough structure to stand four layers tall. Making a frosting with mascarpone cheese took some finesse. The high fat content of mascarpone can cause it to separate when overagitated. Replacing half of the mascarpone with tangy cream cheese, which has stabilizers to ensure a creamy texture, made our frosting foolproof. We whipped the two cheeses with sugar until just light and fluffy, making sure not to overwhip. Next we folded in whipped cream, which we enhanced with gelatin to give it more structure; this gave our frosting a lighter texture that was still stable enough to be stacked between the cake layers. The final addition of a vibrant homemade blackberry jam made for a sophisticated frosting that was as beautiful as it was delicious. For a look as modern as the flavor profile, we didn’t frost the sides of our cake; instead, we merely scraped them with a thin veil of our frosting so the lovely layers peeked through.

Serves 12 to 16

Be sure to let the cake pans cool completely before repeating with more batter.

BLACKBERRY JAM
1 pound (3¼ cups) blackberries, plus extra for garnishing cake
1 cup (7 ounces) granulated sugar

CAKE
2½ cups (10 ounces) cake flour
2 cups (14 ounces) granulated sugar
1 tablespoon baking powder
½ teaspoon salt
10 large eggs (4 whole, 6 separated), room temperature
12 tablespoons unsalted butter, melted and cooled
¼ cup water
2 teaspoons grated lemon zest plus ¼ cup juice (2 lemons)
4 teaspoons vanilla extract

MASCARPONE FROSTING
1 teaspoon unflavored gelatin
2 tablespoons water
8 ounces mascarpone cheese, room temperature
8 ounces cream cheese, softened
¼ cup (1 ounce) confectioners' sugar
1 teaspoon vanilla extract
⅛ teaspoon salt
2 cups heavy cream, chilled

1. FOR THE BLACKBERRY JAM: Process blackberries in food processor until smooth, about 1 minute; transfer to large saucepan. Stir sugar into blackberries and bring to boil over medium-high heat. Boil mixture, stirring often and adjusting heat as needed, until thickened and measures 1½ cups, 15 to 20 minutes. Transfer jam to bowl and let cool completely. (Jam can be refrigerated for up to 1 week; stir to loosen and bring to room temperature before using.)

2. FOR THE CAKE: Adjust oven rack to lower-middle position and heat oven to 325 degrees. Lightly grease two 8-inch round cake pans, line with parchment paper, grease parchment, and flour pans. Whisk 1¼ cups flour, ¾ cup sugar, 1½ teaspoons baking powder, and ¼ teaspoon salt together in large bowl. Whisk in 2 eggs and 3 yolks, 6 tablespoons butter, 2 tablespoons water, 1 teaspoon lemon zest and 2 tablespoons juice, and 2 teaspoons vanilla until smooth.

3. Using stand mixer fitted with whisk attachment, whip 3 egg whites on medium-low speed until foamy, about 1 minute. Increase speed to medium-high and whip whites to soft, billowy mounds, about 1 minute. Gradually add ¼ cup sugar and whip until glossy, soft peaks form, 1 to 2 minutes. Whisk one-third of whites into batter to lighten. Using rubber spatula, gently fold remaining whites into batter in 2 batches until no white streaks remain.

4. Divide batter evenly between prepared pans and smooth tops with rubber spatula. Bake until toothpick inserted in center comes out clean, 30 to 40 minutes, switching and rotating pans halfway through baking.

5. Let cakes cool in pans on wire rack for 10 minutes. Remove cakes from pans, discarding parchment, and let cool completely on rack, about 2 hours. Repeat steps 2 through 5 with remaining cake ingredients to make two more cake layers.

6. FOR THE MASCARPONE FROSTING: Sprinkle gelatin over water in bowl and let sit until gelatin softens, about 5 minutes. Microwave mixture in 5‐second increments until gelatin is dissolved and liquefied.

7. Using clean, dry mixer bowl and whisk attachment, whip mascarpone, cream cheese, sugar, vanilla, and salt on medium speed until light and fluffy, about 30 seconds, scraping down bowl as needed; transfer to large bowl. Using clean, dry mixer bowl and whisk attachment, whip cream on medium‐low speed until foamy, about 1 minute. Increase speed to high and whip until soft peaks just begin to form, about 1 minute, scraping down bowl as needed. Slowly pour in gelatin mixture, and continue to beat until stiff peaks form, about 1 minute. Using rubber spatula, stir ⅓ of whipped cream into mascarpone mixture to lighten; gently fold remaining whipped cream into mixture in 2 batches. Stir room temperature blackberry jam to loosen, then gently fold jam into mascarpone mixture until combined. Refrigerate frosting for at least 20 minutes or up to 24 hours before using.

8. Line edges of cake platter with 4 strips of parchment to keep platter clean and place small dab of frosting in center of platter to anchor cake. Place 1 cake layer on platter. Spread 1 cup frosting evenly over top, right to edge of cake. Repeat with 2 more cake layers, pressing lightly to adhere and spreading 1 cup frosting evenly over each layer. Top with remaining cake layer and spread 1½ cups frosting evenly over top. Spread remaining frosting evenly over sides of cake to cover with thin coat of frosting. Run edge of offset spatula around cake sides to create sheer veil of frosting. (Cake sides should still be visible.) Refrigerate cake for 20 minutes. Garnish with blackberries and carefully remove parchment strips before serving. (Cake can be refrigerated for up to 24 hours; bring to room temperature before serving.)