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Grapefruit olive oil slice sitting on a dessert plate.

Grapefruit Olive Oil Cake

Lisa Flinn
Enjoy citrus season with this light and refreshing Grapefruit Olive Oil Cake! It's made with fine polenta, extra-virgin olive oil and red grapefruit zest. After the cake comes out of the oven, it gets a delicious grapefruit syrup soak that should not be skipped. Not only does the bittersweet syrup pair well with the fruity flavor of the extra-virgin olive oil, it also adds a lovely shine to the cake.
5 from 1 vote
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Prep Time 20 minutes
Cook Time 35 minutes
Total Time 55 minutes
Course Cakes, Dessert
Cuisine Italian
Yields 8 Servings

INGREDIENTS

Grapefruit Olive Oil Cake 

  • 1 ¼ Cup (150g) All-Purpose Flour
  • ½ Cup (70g) Polenta or Cornmeal see note below
  • 1 ¼ Teaspoon Baking Powder
  • ½ Teaspoon Fine Salt
  • 1 Cup (200g) Granulated White Sugar
  • 2 to 3 Tablespoons Grapefruit Zest finely grated
  • 3 Whole Large Eggs room temp
  • ½ Cup + 2 Tablespoons (124g) Extra-Virgin Olive Oil
  • ⅓ Cup (76g) Full-Fat Sour Cream or Plain Greek Yogurt room temp
  • 2 Tablespoons Grapefruit Juice freshly squeezed
  • 1 Teaspoon Vanilla Extract

Grapefruit Simple Syrup

  • ¼ Cup Grapefruit Juice freshly squeezed & strained
  • ¼ Cup (50g) White Sugar

Instructions
 

  • Preheat Oven & Prep Pan - Position a rack in the center of the oven and preheat it 350ºF (180ºC). Prep a round 8-inch (20 cm) or 9-inch (23 cm) cake pan by greasing and lining the bottom with parchment paper. See note below.
  • Combine Dry Ingredients - In a medium sized bowl, whisk together all-purpose flour, polenta, baking powder and salt. 
    1 ¼ Cup (150g) All-Purpose Flour
    ½ Cup (70g) Polenta or Cornmeal
    1 ¼ Teaspoon Baking Powder
    ½ Teaspoon Fine Salt
  • Combine Sugar & Zest - In a large mixing bowl, combine white sugar and finely grated grapefruit zest. Use your fingers to rub the mixture together until it becomes fragrant and fully mixed.
    1 Cup (200g) Granulated White Sugar
    2 to 3 Tablespoons Grapefruit Zest
  • Combine Wet Ingredients - Add the eggs and using a hand mixer, whisk for a few minutes until well combined. Next, with the mixer on medium-low speed, slowly drizzle in extra-virgin olive oil and mix until combined. Then, add sour cream, grapefruit juice and vanilla extract and mix until incorporated. Scrape down the sides and bottom of the bowl as needed.
    3 Whole Large Eggs
    ½ Cup + 2 Tablespoons (124g) Extra-Virgin Olive Oil
    ⅓ Cup (76g) Full-Fat Sour Cream or Plain Greek Yogurt
    2 Tablespoons Grapefruit Juice
    1 Teaspoon Vanilla Extract
  • Combine Wet & Dry Ingredients - Sift in the dry ingredients and mix on the lowest speed until just combined. Do not overmix.
  • Bake - Pour cake batter into your prepared cake pan and bake for 35 to 40 minutes or until an inserted toothpick in the middle of the cake comes out clean. After 30 minutes of baking, if the cake is getting too browned, you can loosely tent the top of the cake pan with foil.
  • Make Grapefruit Syrup - As the cake is baking, make the grapefruit simple syrup by combining sugar and grapefruit juice in a small saucepan. Over medium heat, bring it to a boil and stir until sugar has dissolved, about 3 to 4 minutes. It will thicken as it cools.
    ¼ Cup Grapefruit Juice
    ¼ Cup (50g) White Sugar
  • Soak With Syrup - Once the cake is out of the oven, let it cool in the pan for 5 to 8 minutes. Then run a paring knife around the edge of the cake and invert it onto a wire rack. Remove parchment paper if used. Then use another cooling rack to flip it right side up. Grab a toothpick and poke holes through the top of the cake. Finally, brush all of the the syrup onto the warm cake, including down the sides. Cool completely before serving and enjoy!

Notes

Polenta - I used instant polenta which has more of a fine grind, but feel free to use regular polenta. You can also use fine or medium grind cornmeal. The medium grind cornmeal will give you more of a crunchy texture.
Cake Pan - If baking in a 9-inch (23 cm) cake pan, the cake will take less time to bake. Check after 30 minutes.
Grapefruit Zest - Depending on the size of your grapefruit, you may need to zest 2 of them. For more grapefruit flavor, add 3 tablespoons.
Soaking Cake with Syrup - Set the cooling rack over a baking pan to catch any access syrup drippage.
Keyword citrus olive oil cake, cornmeal cake, grapefruit olive oil cake, grapefruit polenta cake, polenta cake
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