step 1
Preheat and Prep: Preheat the oven to 350°F (175°C). Line two half-sheet pans with parchment paper.
step 2
Make the Vanilla Cake: In a large mixing bowl, whisk together the Yolks from the Eggs (8), ¼ cup of Granulated Sugar (4 Tbsp), Milk (1/3 cup), Oil (1/3 cup), and Vanilla Extract (1 Tbsp) until smooth and well combined.
step 3
Sift the All-Purpose Flour (1/2 cup) and Corn Starch (1/3 cup) into the egg yolk mixture and mix until just incorporated.
step 4
In the bowl of a stand mixer fitted with the whisk attachment, beat the egg whites and Cream of Tartar (1 tsp) until no liquid egg whites remain. Gradually add the remaining Granulated Sugar (1/2 cup) with the mixer on low, then increase speed and beat to a soft peak.
step 5
Gently fold ⅓ of the meringue into the egg yolk batter until only slight streaks remain. Add the next ⅓ and fold again. Finally, add the remaining meringue, folding until no white streaks remain.
step 6
Pour the batter into one of the prepared pans and bake for 20-25 minutes, or until the cake is fully set.
step 7
Cool the Cake: Place a piece of parchment paper over each cake layer. Flip the cakes onto a cooling rack, and gently remove the parchment from the bottom. Let the cakes cool to room temperature.
step 8
Make the Chocolate Cake: In a large mixing bowl, whisk together the yolks from the Eggs (8), ¼ cup of Granulated Sugar (4 Tbsp), Milk (1/3 cup), Oil (1/3 cup), and Vanilla Extract (2 tsp) until smooth and well combined.
step 9
Sift the All-Purpose Flour (1/2 cup), Corn Starch (4 Tbsp), and Dutch Processed Cocoa Powder (4 Tbsp) into the egg yolk mixture, mixing until just combined.
step 10
Using the stand mixer, repeat the same meringue-making process with the egg whites, Cream of Tartar (1 tsp), and remaining Granulated Sugar (1/2 cup) as for the vanilla cake.
step 11
Fold the meringue into the chocolate batter in thirds, mixing until no white streaks remain.
step 12
Pour the batter into the second prepared pan and bake at 350°F for 20-25 minutes, or until done.
step 13
Swiss Meringue Buttercream: In a heatproof bowl that fits over a double boiler, whisk together the whites from the Eggs (5) and Granulated Sugar (1 1/2 cups). Place the bowl over simmering water and whisk until the sugar is completely dissolved or the mixture reaches 160°F (71°C).
step 14
Transfer the mixture to the bowl of a stand mixer fitted with the whisk attachment. Beat on high until you have a thick, fluffy meringue that has cooled to room temperature.
step 15
Switch to the paddle attachment. Gradually add the Unsalted Butter (2 cups) a piece at a time, until fully incorporated and smooth. Add the Kosher Salt (1 pinch) and Vanilla Extract (2 tsp), mixing until well combined.
step 16
Strawberry Swiss Meringue Buttercream: In a heatproof bowl over a double boiler, whisk together the whites from the Eggs (8) and Granulated Sugar (2 1/4 cups). Heat until the sugar is dissolved or the temperature reaches 160°F (71°C).
step 17
Transfer to the stand mixer and beat with the whisk attachment until the meringue is thick, fluffy, and cool to room temperature.
step 18
Switch to the paddle attachment. Gradually add the Unsalted Butter (3 cups) one piece at a time, until fully incorporated. Add the Kosher Salt (1 pinch), Vanilla Extract (1 tsp), and Strawberry Powder (1/2 cup), mixing on low until smooth and combined.
step 19
Chocolate Swiss Meringue Buttercream: In a heatproof bowl over a double boiler, whisk together the whites from the Eggs (5) and Granulated Sugar (1 1/2 cups). Heat until the sugar is dissolved or the temperature reaches 160°F (71°C).
step 20
Transfer to the stand mixer and beat with the whisk attachment until thick, fluffy, and cooled to room temperature.
step 21
Switch to the paddle attachment. Gradually add the Unsalted Butter (2 cups), a piece at a time, until smooth. Add the Kosher Salt (1 pinch), Vanilla Extract (1 tsp), Dutch Processed Cocoa Powder (1/2 cup), and melted Dark Chocolate (1/2 cup), mixing until well combined and smooth.
step 22
Assembly: Place the vanilla cake on a large cutting board. Spread an even layer of strawberry Swiss meringue buttercream over the entire surface, about ¼ inch thick. Gently place the chocolate cake on top, aligning the edges.
step 23
Cut the stacked cake in half lengthwise. Starting from one end of one half, carefully roll the cake into a tight spiral until you reach the end. Place the end of the rolled cake onto the other half and continue rolling to create a larger spiral.
step 24
Wrap the rolled cake in plastic wrap, turn it on its side so it stands like a round cake, and refrigerate until the buttercream is firm.
step 25
Place the chilled cake onto a cake board that fits snugly underneath. Apply a thin layer of buttercream (crumb coat) over the entire cake to seal in crumbs and create an even surface. Chill again until the crumb coat is set.
step 26
Once chilled, transfer the cake to a cake stand. Prepare piping bags with vanilla, chocolate, and strawberry SMB, each fitted with an 806 round tip.
step 27
Pipe a vertical row of buttercream dots down the side of the cake, alternating between chocolate, strawberry, and vanilla. Use a small offset spatula or the back of a spoon to gently pull each dot to create a petal shape.
step 28
Pipe another row of alternating dots at the end of the first row, pull them to form petals, and continue around the cake, piping and pulling dots in rows until the entire cake is covered.
