Recipe summary

Hands-on time:
25 mins. to 30 mins.
Baking time:
20 mins. to 25 mins.
Total time:
55 mins. to 1 hrs 5 mins.
Yield:
Two 8" or 9" round layers, one 13" x 9" x 2" cake, or 24 cupcakes
This recipe first appeared in our King Arthur Flour Whole Grain Baking book in 2006. Pairing whole wheat and citrus makes for an excellent combination. The whole wheat's sweetness is brought out by the tang of the citrus; and the earthy flavor of the wheat marries well with that of grapefruit. Using oil and egg whites makes for a very light cake that holds its structure well with nary a sign of heaviness from the whole grains.
Volume Ounces Grams

  • 2 cups King Arthur 100% White Whole Wheat Flour
  • 2 teaspoons baking powder
  • 1/2 teaspoon salt
  • 5 large egg yolks, whites reserved
  • 1/2 cup vegetable oil
  • 1 1/2 cups granulated sugar
  • 1/3 cup water
  • 1/4 cup fresh grapefruit juice
  • 1 tablespoon freshly grated grapefruit peel (zest)
  • 5 large egg whites
  • 1/4 teaspoon cream of tartar

Directions

  1. 1) Preheat the oven to 350F. Lightly grease two 9" round cake pans, line with parchment, and lightly grease the parchment. Set aside.
  2. 2) Whisk together the flour, baking powder, and salt in a medium bowl; set aside.
  3. 3) Combine the egg yolks and oil. Beat at low speed, using your stand mixer or a hand mixer. Slowly add the sugar as the mixture thickens. Add the water and grapefruit juice. Beat on medium speed for 3 minutes, stopping occasionally to scrape the bottom and sides of the bowl. Gently fold in the flour mixture and grapefruit zest with a wide rubber spatula.
  4. 4) In a separate bowl, free of any oil or grease, beat the egg whites until foamy. Add the cream of tartar and continue to beat on high speed until soft peaks form.
  5. 5) Gently fold the beaten whites into the batter by thirds. Combine only until traces of white remain; don't over-mix.
  6. 6) Divide the cake batter between the two pans and bake for 20 to 25 minutes, until a cake tester tests clean and the cake begins to pull away from the sides of the pan. For a 9" x 13" pan, bake 25 to 35 minutes. For cupcakes, bake 15 to 18 minutes.
  7. 7) Cool in the pan for 10 minutes before turning out onto a rack to cool completely. Frost as desired; see suggestions in "tips" at left.
  8. Yield: two 9" round cake layers; one 9" x 13" x 2" sheet cake, or 24 cupcakes.

Tips from our bakers

  • Cream Cheese Frosting is delightful on this cake, as is Italian Buttercream. A few drops of pink food coloring combined with a drop or two of orange food coloring will give you a beautiful "pink grapefruit" colored icing.