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Grapefruit Poppy Seed Cake

Yield 1 3-layer, 8-inch cake

Tender grapefruit  poppy seed cake, layered with grapefruit curd and cream cheese frosting.

Ingredients

For the Grapefruit Curd (recipe source: Cookie Dough and Oven Mitt)

For the Grapefruit Poppyseed Cake (recipe adapted from: Technicolor Kitchen)

For the Vanilla Cream Cheese Frosting (recipe source: Technicolor Kitchen)

Instructions

For the Grapefruit Curd

  1. In two bowls, divide the egg whites and yolks. Set aside the egg whites for another recipe.
  2. Add the zest of one large grapefruit in with the egg yolks and mix briefly.
  3. In a medium saucepan, add the sugar, salt and cornstarch and whisk until combined.
  4. Add in the grapefruit juice and whisk until incorporated into the sugar mixture. Place the saucepan over medium heat and let it come up to a boil. Whisking occasionally.
  5. Once it comes to a boil, let it boil for 2 minutes, whisking constantly to avoid burning.
  6. Slowing pour about 1/2 cup of the juice mixture into the egg yolks that you've set aside, whisking while you pour. Continue whisking to avoid the yolks from cooking. This is tempering the yolks.
  7. Add the tempered yolks into the saucepan with the juice and whisk until incorporated.
  8. Let the grapefruit curd come up to a boil and boil for about 5 minutes, until thickened.
  9. Remove from heat and add the cold butter. Whisk until the butter is melted and well combined.
  10. Place in a shallow dish and cover with plastic wrap. Be sure that the plastic wrap is touching the curd, otherwise it may form a skin. Let set in the refrigerator 2-3 hours. Can be made several days in advance of the cake.

For the Grapefruit Poppyseed Cake

  1. Preheat the oven to 350 degrees F. Butter or spray three 8-inch round cake pans and line the bottoms with parchment paper. Butter or spray the paper.
  2. Combine the flour, 1 1/2 cups sugar, baking powder, salt and poppy seeds in the large bowl of a stand mixer fitted with the paddle attachment. Beat on low speed to blend the ingredients and break up any lumps, about 30 seconds.
  3. Add the butter, grapefruit zest and 1 cup of the buttermilk to the flour mixture. Beat on low until completely mixed, then raise the speed to medium and beat for two minutes to lighten and aerate the batter.
  4. In a medium bowl, combine the egg whites with the remaining 1/4 cup buttermilk and whisk to blend thoroughly. Add this mixture to the batter in 2-3 additions, scraping down the sides of the bowl and beating only enough to incorporate. Divide the batter among the prepared pans.
  5. Bake for 23-25 minutes (mine were done at 24 minutes, so keep an eye on them around 20 minutes). Let the cakes cool in the pans for 10 minutes.
  6. While the cakes are cooling, make the grapefruit syrup: in a small saucepan, combine the remaining 1/4 cup sugar and grapefruit juice. Bring to a boil, stirring to dissolve the sugar.
  7. Turn the cake layers onto wire racks and gently poke holes on the top of each cake layer with a toothpick. Generously brush each cake layer with the grapefruit syrup. Let cool completely.

For the Vanilla Cream Cheese Frosting

  1. Split the vanilla beans lengthwise and scrape the seeds into the sugar with the back of a knife.
  2. In a large bowl of a stand mixer fitted with the paddle attachment, beat the cream cheese and butter on medium speed until light and fluffy. Gradually add in the sugar, 1 cup at a time, beating well after each addition and scraping down the sides of the bowl. Continue to beat until very fluffy, about 3-4 minutes. Add the vanilla extract and beat well.

Assembly

  1. Place one cake layer, bottom side down, on a cake plate and pipe a rim of frosting around the edge of the cake layer to create a barrier for the curd.
  2. Evenly spread about 2/3 cup of the grapefruit curd on the cake layer.
  3. Repeat with the second cake layer, another boarder of frosting and 2/3 cup curd.
  4. Place the final cake layer, top side down, on top. Give the cake a quick crumb coat and chill for 20-30 minutes in the refrigerator or 10-15 minutes in the freezer before frosting the entire cake.

Recipe by Cake by Courtney at