Chiffon Cake:

Separate 6 eggs into yolks and whites, and let them come to room temperature (about 30 min).

Preheat the oven to 340 F (170 C). Prepare two 9" round cake pans by lining the bottoms with parchment paper. Do not grease the parchment paper or the sides of the pans. Soak 2 cake strips in cold water for 5 minutes. Then shake off excess water but do not wring. And place the soaked cake strips around the cake pans.

In a large mixing bowl, sift together 1 2/3 cups of cake flour, 2 tsp of baking powder, 1/3 cup of granulated sugar, and 3/4 tsp of salt. Whisk together to combine. Then add in 6 egg yolks, 1/2 cup of vegetable oil, 2/3 cup of water, 1/2 tsp finely grated orange zest, and 2 tsp of vanilla extract.

Beat this together with an electric mixer until the mixture is smooth and well-blended.

In the bowl of your stand mixer, add in the 6 room temperature egg whites and 1 tsp of cream of tartar, and with the whisk attachment beat on medium speed until it looks frothy, about 2 minutes. Then turn the speed up to medium-high, and very slowly add in 1/2 cup of granulated sugar while continuing to beat. When all the sugar has been added, turn the speed up to high and beat until you see stiff glossy peaks.

One third at a time, gradually and very gently fold in this meringue into the cake mixture until very well combined. Distribute the batter evenly into the prepared round cake pans.

Bake in the preheated oven at 340 F (170 C) for 35 to 40 minutes or until the cake springs back when touched lightly at the center. Let the cakes reset in the pans for 5 minutes to cool a bit. If the cakes haven't shrunk away and detached from the sides of the pans after 5 minutes, run a sharp knife along the edges to unstick them. Then invert the round cake pans onto metal racks, lift off the pans, and peel off the parchment paper the cakes were baked with. Let the cakes cool on the metal racks to room temperature.

Mango Swiss Buttercream:

Take 2 cups of unsalted butter, cut it into 1-inch cubes, and let it come to room temperature.

In a large heat-proof bowl like glass or stainless steel, add in 5 egg whites, 1 1/2 cups of sugar, and 1 tsp of salt. Whisk together until they are combined.

Set up a double boiler and heat the egg white mixture in a low heat water bath while continuing to whisk, till the sugar is dissolved (when it feels sticky to touch, and you hardly feel the grains of sugar anymore). If you have a thermometer, it needs to reach 160 F (70 C).

Take it off the water bath. Transfer the mixture into the bowl of your stand mixer. With the whisk attachment, beat this mixture until glossy and stiff peaks form. Let it cool down completely to room temperature.

When it is back to room temperature, continue beating and slowly add the 2 cups precut room temperature (unsalted) butter one cube at a time. The mixture might start looking curdled, but do not worry, that's just because the butter is too cold and not fully mixed in. Just continue mixing with the electric mixer until it looks smooth.

When the butter is fully mixed in and the frosting looks smooth, add in 2 tsp of vanilla extract and mix it in. Then transfer about 1 1/2 cups of this frosting into a piping bag fitted with a large flower petal tip (I like to use a #127 tip for this). Set this aside at room temperature for making a border at the end.

Take a blender, and add in 2 cups of chopped mangoes (from about 2 fresh mangoes, sliced, or frozen mangoes that are completely thawed). Blend very well until it is a smooth mango puree.

Add the mango puree into the remaining Swiss-meringue buttercream frosting in the stand mixer. Mix this in with the electric beater until it's smooth. Scrape down the bowl to ensure that everything is mixed in. Let this rest at room temperature until you're ready to use it. This will be used as the filling and frosting the top surface and top half of the sides of the cake.

Mango Glaze:

Take a blender, and add in 2 cups of chopped mangoes (from about 2 fresh mangoes, sliced, or frozen mangoes that are completely thawed).

Add in 2 tbsp of granulated sugar and 1 tbsp of cornstarch. Blend this mixture very well until it is a smooth puree.

Pour this mixture into a small skillet or saucepan and heat over medium heat. and bring to a boil. When it starts to boil, let it cook for 1 minute, while stirring to make sure it's not sticking to the bottom of the pan. The heat will activate the thickening properties of the cornstarch. After 1 minute, turn off the heat. Then divide equally into two separate bowls, and let it cool to room temperature.

Assembling the Cake:

Place a cake board that's larger than 9" (we use a 10" cake board) on a revolving cake stand. Place one of the chiffon rounds on the cake board.

Spread about 2 cups, about a 1/2" thick layer, of the mango swiss meringue buttercream on top, creating an even and flat layer as much as possible.

Spread half of the mango jam on top of this layer of mango buttercream, creating an even and flat layer as much as possible.

Place the second layer of chiffon cake on top. Cover the top and sides of the cake with a thin layer of the mango buttercream. Use a bench scraper to smoothen out this thin crumb coat while rotating the revolving cake stand. This thin crumb coat should catch any crumbs. Place this cake in the fridge for 20 minutes for the crumb coat to firm up a bit. Keep the unused frosting at room temperature.

When the crumb coat has hardened, apply a final layer of the mango buttercream around the sides of the cake, as well as the top. Again, use the bench scraper to smoothen out the surfaces as much as possible while rotating the revolving cake stand. You can use the remaining mango frosting at this point.

Take an icing comb, and create a pattern around the sides of the cake. Clean up and smoothen the top edges and surface of the cake as much as possible. Clean up excess frosting at the base as needed.

Take the plain white frosting that was set aside earlier, and create a border of petals around the top circumference of the cake. Starting with the wider end of the tip touching the cake and the tip parallel to the cake surface, starting right at the outer edge of the cake moving about an inch towards the center of the cake, squeeze while gently rocking your hand back and forth to create the petals, increasing the angle of the tip as you go to become perpendicular to the surface of the cake at the end. Repeat this till you've made ruffles around the entire cake.

Spread the remaining half of the mango jam evenly on the top surface, making sure it reaches the frosting wall.

Refrigerate overnight for the layers to set, and set it out at room temperature for at least 30 minutes before serving to let the buttercream soften a bit. Enjoy!