Toasted Sesame and Citrus Wedding Cake

Preparation

1. Prepare the Chiffon Cake Layers

   1. Step 1

      Heat oven to 350 degrees. Line the bottoms of 3 half-sheet pans (13-by-18-by-1-inch) with sheets of parchment.

   2. Step 2

      Carefully crack eggs into a bowl without breaking the yolks. Pluck out yolks one at a time with clean fingertips, transferring to a large bowl. Transfer the egg whites to the bowl of a stand mixer; set aside. To yolks, add 1 cup/240 grams water, the oil, vanilla and 3 cups/600 grams granulated sugar; whisk until smooth.

   3. Step 3

      In a very large bowl, whisk flour, baking powder and salt. Pour yolk mixture into dry ingredients and gently stir to combine. (Small lumps are OK.)

   4. Step 4

      Using the whisk attachment, beat egg whites in the stand mixer on medium-high speed until a soft peak forms, about 2 minutes. With the mixer running, stream in remaining 1 cup/200 grams granulated sugar and continue whisking until a glossy, floppy meringue forms, another 3 to 4 minutes.

   5. Step 5

      Scrape one-third of the meringue into yolk mixture and gently fold with a spatula until mixture is loosened. Add remaining meringue and fold until batter feels billowy and some white streaks remain. Divide batter evenly among prepared pans. Smooth the surfaces evenly with an offset spatula and transfer to the oven, working in batches if needed.

   6. Step 6

      Bake until centers of cakes spring back to the touch and edges are lightly golden, about 18 minutes. If oven heat is uneven, switch the positions of the pans halfway through. Let cakes cool completely in pans until ready to use. The cakes, tightly wrapped in their pans, can be refrigerated for up to 1 week, or frozen for up to 1 month.

2. Prepare the Sesame Crunch

   1. Step 7

      If the oven is off, heat to 350 degrees. Line a 13-by-18-inch sheet pan with a sheet of parchment and coat with nonstick spray.

   2. Step 8

      In a medium bowl, whisk egg whites, light brown sugar, vanilla and salt until glossy, about 3 minutes. Stir in sesame seeds. Pour batter onto prepared pan and smooth to the edges with a small offset spatula.

   3. Step 9

      Bake for 6 minutes. Remove from oven and use a bench scraper or butter knife to chop. Bake for another 5 to 6 minutes, or until pieces no longer feel sticky.

   4. Step 10

      Let sesame crunch cool completely in the pan; it will continue to crisp as it rests. If it still seems chewy after cooling, bake for an additional 3 to 4 minutes. Finely chop into tiny clusters. The sesame crunch can be stored in an airtight container at room temperature for up to 2 weeks, or in the freezer for up to 1 month.

3. Prepare the Citrus Compote

   1. Step 11

      Wash and scrub the oranges and lemons. Cut each in half crosswise. Heat a large pot or Dutch oven over medium-low and add fruit, cut sides down. They should sizzle upon contact. Let sear, undisturbed, for about 10 minutes, until the cut sides of the fruit are blackened in spots. Use tongs to carefully flip each piece and continue to cook for another 10 minutes, until the peel is softened and charred in spots.

   2. Step 12

      Transfer citrus to a cutting board to cool. Add 8 cups water to the pot, scrape the bottom and bring water to a simmer.

   3. Step 13

      Peel the fruit, and reserve citrus segments. (You should have about 2 cups segments.) Roughly chop peels.

   4. Step 14

      Add chopped peels to the simmering water and simmer, stirring occasionally, until peels are tender, 10 to 15 minutes. Drain peels in a colander, discarding the water.

   5. Step 15

      Press citrus segments through a strainer into a small bowl to yield ½ cup juice. Set juice aside for the charred citrus soak (see Make the Citrus Soak).

   6. Step 16

      Transfer spent pulp in the strainer to the pot, and add granulated sugar, cooked peels and 1 cup/240 grams water. Bring to a simmer over medium-low heat and cook, stirring occasionally, until mixture is thickened and saucy, 25 to 30 minutes. If mixture looks tight or dry, add ¼ cup/60 grams water at a time and continue to cook until peels are tender.

   7. Step 17

      Remove from heat and use an immersion blender or food processor and pulse until the mixture is smoothed out but retains a little texture. Stir in citric acid, if using. The compote should taste sweet and sour. Add more citric acid if desired. Let cool completely. The compote can be stored in an airtight container in the refrigerator for up to 2 weeks, or in the freezer for up to 1 month.

4. Make the Citrus Soak

   1. Step 18

      Make the citrus soak: Combine ½ cup reserved charred citrus juice (see Step 5 of Prepare the Citrus Compote) with ½ cup/120 grams water, the fresh lemon juice and granulated sugar in a small saucepan. Gently warm over low heat, stirring occasionally, until sugar melts, about 5 minutes. Cool completely. The soak can be refrigerated in an airtight container for up to 1 week, or frozen for up to 1 month. Thaw before use.

5. Prepare the Buttercream

   1. Step 19

      Add egg whites and granulated sugar to a stand mixer bowl or other large heatproof bowl and set over a medium saucepan of steaming water set over low heat. (The water should not touch the bottom of the bowl.) Whisk continuously until mixture registers 155 degrees, about 10 minutes.

   2. Step 20

      Remove the bowl from the pot and fit into the stand mixer with the whisk attachment. Whisk on medium-high speed until the mixture has cooled slightly, about 4 minutes. Add confectioners’ sugar and mix on low speed to combine. Mix in vanilla and salt.

   3. Step 21

      Check the temperature of the meringue with a clean fingertip: It should be room temperature. With the mixer on medium speed, add butter, piece by piece, until fully incorporated, then increase speed to medium-high and whisk until smooth and fluffy, another 3 to 5 minutes.

   4. Step 22

      If the buttercream looks runny, refrigerate for 10 to 15 minutes to cool and then beat again until it is creamy and spreadable. With machine running, add sesame oil and mix to combine, then add tahini and whisk just until incorporated. Taste and add more salt if desired. The buttercream can be refrigerated in an airtight container for up to 2 weeks, or frozen for up to 1 month. If frozen, thaw overnight in the refrigerator, then bring to room temperature before use (this will take at least 2 hours and possibly more).

6. Assemble the Cake Tiers

   1. Step 23

      Line an 8-inch round cake form or pan (at least 3 inches deep) with plastic wrap, being sure to leave plenty of overhang. Repeat with a 10-inch round cake form or pan (also at least 3 inches deep). Peel off and discard parchment from cake layers.

   2. Step 24

      Cut out the 8-inch cake rounds: Using the bottom of the 8-inch pan as a guide, trace and cut out an 8-inch circle with a small serrated knife on the upper left corner of one of the cake sheets. Trace and cut another 8-inch circle on the lower right corner of the sheet. Trace and cut a half-moon shape on the upper right corner of the sheet, and then the lower left corner. Lay those half-moons over a whole circle and cut out strips of cake from the scraps to complete the circle. You will have three 8-inch rounds total (including the two half-moons and their cake strips).

   3. Step 25

      Build the 8-inch cake tier: Invert one cake round into the bottom of the plastic wrap-lined pan. Brush cake with 3 tablespoons citrus soak. Spoon ¾ cup buttercream on top, and spread it evenly with a small offset spatula. Dollop ½ cup citrus compote on top of buttercream. Scatter about ¾ cup sesame crunch on top.

   4. Step 26

      Arrange the two half-moons and strips of cake on top to form the second 8-inch cake layer. Apply another 3 tablespoons citrus soak, then ¾ cup buttercream, followed by another ½ cup citrus compote, plus another ¾ cup sesame crunch. Place the remaining 8-inch cake round on top and brush on 3 tablespoons citrus soak. Wrap the cake pan securely with plastic wrap and refrigerate for at least 12 hours.

   5. Step 27

      Cut out the 10-inch cake rounds: Using the bottom of the 10-inch pan as a guide, trace and cut a 10-inch circle with a small serrated knife on the left side of one of the cake sheets. Trace and cut part of another 10-inch circle on the right side and a smaller crescent moon on one of the edges. Lay the partial pieces over the whole circle and cut cake scraps to fill in the gaps. Repeat with the third sheet of sponge; you will have four 10-inch rounds total.

   6. Step 28

      Next, build the 10-inch cake tier: Invert one cake round in the bottom of the plastic wrap-lined pan. Brush cake with ¼ cup citrus soak. Spoon 1 cup buttercream on top, and spread it evenly with a small offset spatula. Dollop ⅔ cup citrus compote on top. Scatter about 1¼ cups sesame crunch on top.

   7. Step 29

      Place a cake layer with a missing edge on next and complete the round with its matching pieces. Apply another ¼ cup citrus soak, then 1 cup buttercream, followed by another ⅔ cup compote, plus another 1¼ cups sesame crunch. Repeat this sequence with a third layer of cake and its matching pieces, then place the remaining whole 10-inch cake round on top, and brush on the remaining ¼ cup citrus soak. Wrap the cake pan securely with plastic wrap and refrigerate for at least 12 hours. Both cake tiers can be refrigerated for up to 3 days or, preferably, frozen for up to 3 weeks.

   8. Step 30

      Refrigerate the remaining buttercream until ready to apply. If the cakes have been frozen, they do not need to thaw. Completely frozen cakes are more stable and easier to handle and frost.

7. Frost the Cake Tiers

   1. Step 31

      Let the reserved refrigerated buttercream sit at room temperature for an hour, then whisk with a stand mixer until fluffy and spreadable, about 3 minutes.

   2. Step 32

      Invert the 8-inch cake onto an 8- to 8½-inch cardboard cake round set on top of a baking sheet. Remove the cake form or pan, then peel off the plastic wrap. Dollop 2 cups buttercream on top and use an offset spatula to spread it all the way to the edges of the cake.

   3. Step 33

      Dab 1 cup buttercream on the sides of the cake, smoothing each dab to touch the one before, until none of the cake is visible. Once the sides of the cake are roughly covered in buttercream, run the offset spatula along the top surface again to smooth it out. Run the offset again along the sides of the cake, where excess buttercream will have gathered, to pull away any excess frosting; the cardboard cake round should not be visible. Refrigerate the cake uncovered while you frost the second cake.

   4. Step 34

      Invert the 10-inch cake onto an 11- to 12-inch cardboard cake round, large flat serving platter or decorative cutting board. Remove the cake form or pan, then peel off the plastic wrap. Dollop 2 cups buttercream on top and use an offset spatula to spread it all the way to the edges of the cake.

   5. Step 35

      Dab 2 cups buttercream on the sides of the cake, smoothing each dab to touch the one before, until none of the cake is visible. Once the sides of the cake are roughly covered in buttercream, run the offset spatula along the top again to smooth it out. Run the offset again along the sides of the cake, where excess buttercream will have gathered, to pull away any excess frosting. Refrigerate uncovered for at least 1 hour before stacking the tiers. The tiers can be refrigerated separately for up to 2 days.

8. Assemble the Wedding Cake

   1. Step 36

      If the wedding is in another location, transport the separate tiers in deep cardboard boxes or crates to the venue. To assemble, simply place the 8-inch tier with its cardboard base on top of the 10-inch cake. Decorate the edges and sides of the cake with the fresh citrus and greenery. The cake can be displayed in a shaded, cool outdoor space or in a cool or air-conditioned indoor space for up to 5 hours. Do not let the assembled cake sit in direct sun for longer than an hour. The cake is not in danger of collapsing or shifting because the tiers are so wide, but the buttercream may melt in a warm setting.

9. When Ready to Serve, Cut the Cake

   1. Step 37

      Using a chef’s knife, cut the 8-inch cake into thirds by making two parallel slices, then cut crosswise into 1-inch-thick pieces, wiping the knife clean between each new cut. Cut the 10-inch cake into quarters by making three parallel slices, then cut those pieces crosswise into 1-inch-thick pieces. The 8-inch cake yields about 24 small slices; the 10-inch cake about 36 slices.