Step 1

Arrange a rack in the middle of the oven and heat the oven to 350°F. Line the bottoms of 2 (9-inch wide, 2-inch high) round cake pans with parchment paper. Coat the paper and sides of the pans lightly with cooking spray. Finely grate the zest of 1 large or 2 medium limes until you have 1 teaspoon. Halve the lime(s) and juice until you have 2 tablespoons.

Step 2

Place the lime zest, lime juice, 2 1/4 cups cool heavy cream, 1 1/2 cups granulated sugar, and 2 teaspoons kosher salt in the bowl of a stand mixer (or a large bowl if using an electric hand mixer). Beat with the whisk attachment on medium-high speed until thick and resembles whipped cream, about 3 minutes.

Step 3

Reduce the speed to medium. Add 4 large eggs and 1 large egg yolk one a time, beating well after each addition. The mixture will resemble mayonnaise. Add 1 tablespoon baking powder and beat on low speed until incorporated, about 10 seconds.

Step 4

With mixer still on low speed, add 3 cups sifted cake flour one cup at a time, stopping the mixer and scraping down the sides and bottom of the bowl after each addition, then continue beating until the flour is fully incorporated, about 4 minutes.

Step 5

Divide the batter between the cake pans. Run the tip of an offset spatula through the batter in a figure-eight motion a few times to pop any air bubbles. Smooth the surface with the offset spatula.

Step 6

Place the pans on a large rimmed baking sheet or large roasting pan. Carefully pour enough hot water into the baking sheet or roasting pan to come 1 inch up the sides of the cake pans, making sure not to get any water into the pans.

Step 7

Bake until the cakes are pale golden-brown, spring back when lightly pressed in the center, and a toothpick inserted in the center comes out mostly clean with just a few crumbs, 40 to 50 minutes.

Step 8

Carefully transfer the cakes pans to a wire rack. Let the cakes cool in the pan for 15 minutes. Run an offset spatula around the cakes, then invert the cakes onto the wire rack. Let cool completely. Meanwhile, make the frosting.

Step 9

Finely grate the zest of 1 large or 2 medium limes until you have 1 teaspoon. Halve the lime(s) and juice until you have 2 tablespoons.

Step 10

Place the lime zest, lime juice, 4 cups cold heavy cream, 1 (8-ounce) container mascarpone cheese, 3/4 cup powdered sugar, 1 teaspoon vanilla bean paste or vanilla extract, and 1/2 teaspoon kosher salt in the bowl of a stand mixer fitted (or large bowl if using an electric hand mixer). Beat with the whisk attachment on medium-high speed until thick and fluffy, 6 to 8 minutes. Cover and refrigerate until ready to assemble the cake.

Step 11

Remove the parchment paper from the cakes and flip again. If the cakes are domed, trim the tops with a serrated knife to level them out. Cut each cake in half horizontally to make a total of 4 layers.

Step 12

Peel, pit and chop 4 large, ripe mangoes into 1/4-inch cubes (about 3 cups) and transfer to a medium bowl. Juice 1 large or 2 medium limes until you have 2 tablespoons. Drizzle the lime juice over the mangoes and mix gently until combined. Set aside a couple of tablespoons for garnish.

Step 13

Smear a tablespoon of the frosting onto a cake or serving plate. Center 1 cake layer on the plate. Evenly spread 1 1/2 cups of the frosting onto the cake. Spoon 1/3 of the chopped mango onto the cream and spread evenly across the surface. Repeat layering the cakes, frosting, and mango, ending with the last cake layer. Frost the top and sides of the cake with the remaining frosting. Refrigerate until the whipped cream is firm, at least 1 hour and up to 12 hours.

Step 14

Decorate the top of the cake with the reserved mango just before serving.