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.
This Grapefruit Olive Oil Cake is a variation of my Almond Raspberry Cake. It's delightfully light and is perfect for breakfast, brunch, afternoon tea, dessert and everything in between.
If you're looking for more olive oil dessert recipes, check out my Orange Poppy Seed Cupcakes and Pistachio and Rose Olive Oil Cake!
Jump to:
♡ Why You Will Love This Grapefruit Olive Oil Cake
- Light and Moist - A combination of olive oil and sour cream in the cake keeps the crumb light and soft. The grapefruit simple syrup soak also makes the cake moist, while adding additional flavor.
- Flavor - It has bold citrus flavor, as were using a generous amount of grapefruit zest in the batter. The grapefruit syrup adds a subtle bittersweet flavor that makes you want to go back for more.
- Easy to Make - This one-bowl recipe has very minimal steps and takes less than 15 minutes to prep.
Ingredient Notes
Here are some notes about all the ingredients used in this Grapefruit Olive Oil Cake. Quantities and full instructions are in the recipe card below!
Grapefruit Olive Oil Cake
- Flour - We are using a combination of all-purpose flour and instant polenta, which has more of a fine grind than regular polenta. I've listed some replacements in the "substitution" section below.
- Baking Powder - Helps the cake rise and makes the texture light.
- Fine Salt - Rounds out the flavors and balances the sweetness.
- White Sugar - Sweetens and adds moisture.
- Pink Grapefruit Zest + Juice - Zest adds brightness and flavor and a little bit of the juice lightens the texture of the cake.
- Large Eggs - Adds structure and makes the cake fluffy.
- Extra Virgin Olive Oil - Makes the cake light and moist.
- Sour Cream - Adds structure and moisture. For best results, use full-fat sour cream.
- Vanilla Extract - For flavor.
Grapefruit Simple Syrup
- Grapefruit Juice + White Sugar - Will be cooked for 3 to 4 minutes to create a bittersweet simple syrup for soaking the cake.
*See recipe card for quantities.
Step-By-Step Instructions
Here are step-by-step photos and instructions on how to make these Grapefruit Olive Oil Cake! Please find detailed instructions in the recipe card at the end of this post.
Step 1. Combine Dry Ingredients - In a medium bowl, whisk together all-purpose flour, polenta, baking powder and salt.
Step 2. Combine Sugar & Zest - In a large mixing bowl, combine finely grated grapefruit zest and white sugar. Using your fingers, rub the mixture together until it becomes fragrant.
Step 3. Combine Wet Ingredients - Add the eggs and using a hand mixer, whisk for a few minutes until well combined.
Step 4. Next, with the mixer on medium-low speed, slowly drizzle in extra-virgin olive oil and mix until combined.
Step 5. Then, add sour cream, grapefruit juice and vanilla extract and mix until incorporated.
Step 6. Combine Wet & Dry Ingredients - Sift in the dry ingredients and mix on the lowest speed until just combined. Do not overmix. The batter will be a bit thinner.
Step 7. Bake - Pour the cake batter into a prepared 8-inch (20 cm) round cake pan. Bake at 350ºF (180ºC) for about 35 to 40 minutes or until an inserted toothpick in the middle of the cake comes out clean.
Step 8. Make Grapefruit Syrup - As the cake is baking, make grapefruit simple syrup by combining sugar and grapefruit juice in a small saucepan over medium heat. Bring to a boil and stir until sugar has dissolved, about 3 to 4 minutes. It will thicken as it cools.
Step 9. Poke Holes - Let cake cool in the pan for 5 to 8 minutes, then invert cake onto a cooling rack and flip it right side up. Use a toothpick to poke tiny holes through the top of the cake.
Step 10. Soak the Cake - Brush the syrup all over the warm cake, including the sides. Set the cooling rack over a baking pan to catch any access syrup. Cool completely before serving. Enjoy!
💡 Tip
The tiny holes are visible. If this is a concern, you can lightly dust the top with powdered sugar, cover with whipped cream before serving or just brush the syrup over the warm cake without poking holes. It will still absorb the syrup.
Substitutions & Variations
- Extra Virgin Olive Oil - Use a good quality extra-virgin olive oil. You can also use a light olive oil.
- Polenta - You can use instant or regular polenta. You can easily sub for a fine or medium grind cornmeal too. A medium grind cornmeal will give you more of a crunchy texture. You can also replace with ½ cup (48g) fine almond flour.
- Grapefruit - You can easily substitute with other citrus fruits, such as orange or lemon. If you're replacing with orange, use the zest of one large orange. If replacing with lemon, use the zest of 2 large lemons.
- Full-Fat Sour Cream - You can also use plain Greek yogurt.
Key Equipment
- Bowls
- Electric Mixer - Stand mixer or hand-held mixer
- 8 or 9 Inch (20 or 23 cm) Round Cake Pan
- Parchment Paper
- Toothpick - Used to create tiny holes in the cake to allow syrup to soak inside. If you don't have toothpicks, you can just brush the syrup over the warm cake.
- Small pot - For making grapefruit simple syrup
- Pastry Brush - For brushing syrup on the cake. If you don't have a brush, you can spoon the syrup all over the cake.
Storage
- Room Temperature - Store in an airtight container and on the counter for up to 3 days.
- Refrigerator - Store in an airtight container in the fridge for up to 5 days. Allow to come to room temperature before enjoying.
⭐️ Expert Tips
Use a kitchen scale to weigh all your ingredients. Baking in grams, rather than volume, is the best and most accurate way to bake! All my recipes include gram conversions based on King Arthur's Weight Chart.
If you are not using a kitchen scale, measure your flour correctly. Fluff and aerate your flour first, then spoon into your measuring cup and finally level off with the back of a butter knife. Do not pack it in as it will add too much flour.
Make sure your eggs and sour cream are at room temperature. Quickly bring eggs to room temp by submerging in a bowl of hot tap water for 15 minutes. Swap out the with more hot tap water half way through. Sour cream can quickly be brought to room temperature by microwaving for about 10 seconds.
After 30 minutes of baking, if the cake is getting too browned, loosely tent it with foil.
Brush grapefruit syrup on the cake while still warm. The cake will absorb the simple syrup more easily.
FAQ
Replace all-purpose flour with a 1-to-1 cup gluten-free flour blend. Polenta is naturally gluten-free.
They are both made from corn, however, the consistency of the grain differs.
You May Also Like...
♡ Did you try this recipe?
Please consider leaving a 5-star rating and review below. This provides helpful feedback to myself and other readers. Thank you so much!
📖 Recipe
Grapefruit Olive Oil Cake
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 Flour½ Cup (70g) Polenta or Cornmeal1 ¼ Teaspoon Baking Powder½ 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 Sugar2 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 Eggs½ Cup + 2 Tablespoons (124g) Extra-Virgin Olive Oil⅓ Cup (76g) Full-Fat Sour Cream or Plain Greek Yogurt2 Tablespoons Grapefruit Juice1 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 Juice¼ 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!
Iris says
A wonderful cake with a lovely texture and comforting flavours! The crumb is so soft and soaks in the syrup so beautifully. So delicious!
Lisa says
Aww, I'm so happy you enjoyed the cake! Thank you for trying the recipe!! ❤️