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"Ruby Cake"

I love Ruby Red Grapefruit and wanted to make it into a delicious cake. Nice and fresh with citrus flavor. The filling is made with a unique red ruby chocolate whipped ganache and grapefruit syrup. This is the perfect combination! Not to sweet and still perfect for a citrus cake. Couldn't just make it in layers, this cake is special. So I made it spiral watch me put this delicious cake together. I promise it will be enjoyed! You will need two jelly roll pans or 1/2 sheet cookie pans and parchment paper for this cake.


Unsalted butter, for greasing the pan or baking spray

3/4 cup heavy cream

1 cup (130 grams) all-purpose flour

1/2 teaspoon baking powder

1/2 teaspoon salt

7 large eggs, separated, plus 2 large egg yolks

1 teaspoon citrus extract

1/4 cup fresh red grapefruit juice pulp okay

1 tablespoon zest from a red grapefruit

1 teaspoon distilled white vinegar

3/4 cup (150 grams) granulated sugar

Red ruby chocolate ganache (recipe below)

red grapefruit syrup (recipe below)


For the grapefruit sponge cake:

Preheat the oven to 400 degrees F. Grease the bottom of a rimmed half-sheet pan (18x 12 x2inches) or jelly roll pan and line the bottom with folded parchment paper. (Watch video for instructions) Take the parchment paper that is the same size as pan and fold it in half. Now fold it again. You should have 4 sections. Place this sheet in the bottom of your baking pan. The other sheet of parchment will be used later on top before we flip the cake.

  • Heat the cream in a microwave-safe bowl in the microwave until steaming, about

  • 1 minute. Add to a large mixing bowl and whisk in the flour, baking powder and salt. Whisk until smooth. add in the 10 egg yolks, citrus extract, grapefruit juice and grapefruit zest, whisking until completely smooth. Set aside.

  • In the bowl of your stand mixer fitted with the whisk attachment, whip the egg whites and cream of tater on medium speed until foamy, 1 to 2 minutes. Add the granulated sugar gradually and then raise the mixer speed to medium high and whip until medium stiff peaks form, about 2 minutes.

  • Fold the egg whites into the yolk-flour mixture in 3 additions. Do this carefully to retain an airy mixture. Spread the batter into the prepared pan with the folded parchment paper and smooth the surface.

  • Bake until golden in color and springy to the touch, 14 to 16 minutes. Cool in the pan for 5 minutes. Run an offset spatula around the edges of the cake, place the other piece of parchment over the cake, place the other baking pan over the top of baked cake and flip so that the cake is now in the other pan. There should be parchment on the bottom and top of your cake. You should see the four sections of the cake already lined for you. Let the cake cool completely before adding grapefruit syrup.

Just a reminder that this cake can be made in regular cake pans. You can frost and stack as you would normally.

If using jelly roll pans or 1/2 sheet pans the size may vary. A 18x13x2 is okay to use.


Whipped Chocolate Ganache. Follow this quick video for Ganache. For my Ruby Red cake I placed the ganache in a mixer after it set and whipped until fluffy.

Ganache: Ingredients

  • 3 cups Ruby Chocolate

  • 3 cup heavy whipping cream

  • You will need a hand or stand mixer.

Ruby chocolate is a variety of chocolate introduced in 2017 by Barry Callebaut, a Belgian–Swiss cocoa company. The chocolate is made from "ruby cocoa beans".These are existing botanical cocoa bean varieties that have been identified as having the right attributes to be processed into ruby chocolate. While the exact production method is a trade secret, publications note industry speculation is that ruby chocolate is made with unfermented cocoa beans of Brazil Lavados, which can have a natural red-pink colour. Barry Callebaut registered a patent in 2009 for "cocoa-derived material" from unfermented cocoa beans (or beans fermented for no more than three days) that become red or purple after treating them.


  • Place ruby chocolate into a medium bowl.

  • Heat the cream steamy, and until small bubbles start to form around the outer edges (this can be done in a small pot on the stove, or in the microwave). Be careful it doesn't boil over!

  • Pour the hot cream over the chocolate, let it stand for a few minutes

Whisk the ganache until smooth, then allow it to set. (This can be done at room temperature or in the refrigerator. Whisk it every 10 minutes to keep it smooth and lump-free.)

  • When the ganache is firm but still soft, transfer it to a mixing bowl and whip it on high speed until fluffy (about 3 to 4 minutes) Store in fridge until ready to use.




  • 1 Cup Cane Sugar

  • 1 cup Fresh Grapefruit Juice

  • 1 Tbsp Grapefruit Zest


You can put the sugar and grapefruit zest together the night before. This will bring out even more of the grapefruit flavor.

  • Step 1: Add the grapefruit juice, sugar and zest to a saucepan and bring to a gentle boil over medium heat, stirring occasionally

  • Step 2: Remove from heat as soon as it comes to a boil and liquid is clear of sugar.

  • Step 4: Strain simple syrup into an airtight container Storage: Simple syrup can be stored safely in an airtight container in the refrigerator for up to 1 month.

Assemble the cake

Remove the parchment paper from your cake. Loosen the side with a sharp knife or spatula. Cut the lines in the cool cake. This will be easy because you should be able to see the lines in the cake from the parchment paper.

Generously brush the strips of cake with the grapefruit syrup. Spread the whipped ruby ganache on top of each strip of cake with a small offset spatula. Gently roll up one strip to make a spiral. Matching the ends roll the second strip of cake. Turn the rolled strips onto your serving plate or cake board. You should have two strips left. Gently wrap the third strip around your cake matching the edges when beginning. Continue with the next strip #4 matching the edge of strip. Fill in any gaps and coat the cake with the whipped ganache. You can continue or let the cake chill in the fridge for 15 minutes before continuing with decorating. The video below illustrates this step perfectly. Please watch before you start. It will make it easier to accomplish.


Watch this video before starting your "Ruby Cake"

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