Grapefruit Cake with Buttercream Ruffles

Share this...

Pinterest

Facebook

Twitter

Yummly

Email

Print

This grapefruit cake with buttercream ruffles is an explosion of citrus!  This recipe includes candied grapefruit, grapefruit simple syrup, grapefruit frosting, and a grapefruit cake.  I’ve also got a video tutorial to show you how to make these fun diagonal buttercream ruffles!

This page contains affiliate links which means I may earn a commission as an Amazon Associate (or other affiliate program) from qualifying purchases. I only recommend products that I use and trust. 

Jump to Recipe

Grapefruit Warning

There are 3 whole grapefruits going into this grapefruit cake, so you’re going to have to be a big grapefruit fiend to fully appreciate it.  And just like the actual fruit, this cake is sweet, tangy, and has a slightly bitter after taste.  Kind of strange for a cake, so I’m warning you now.  The flavor does get more mild after a night in the fridge.

On a more serious note, grapefruit can have negative interactions with many common medicines.  This fruit can block enzymes that help our bodies metabolize these drugs which leads them to build up in our system.  If you are taking any medications, read this article by the FDA for more information.

Candied Grapefruit

But onto the best part.  Candied grapefruit.  I’ve done this same method with lemon peel and orange peel so far, but I’ve got to say that this one is my fave.  After you slice off the peel, juice the grapefruit and save that for a little later.

The cooking process first removes the bitter compounds, then candies and sweetens the grapefruit peel.  You don’t want to cut down on any of that time or your peel will be unpleasant.  I used the candied grapefruit on top of the cake, but I think it would be great in between the layers too.

Print Recipe

Grapefruit Simple Syrup

Once you’ve finished the candied grapefruit, save that syrup!  We’re going to use it to add even more flavor to our grapefruit cake.  First taste it to make sure it’s not too bitter.  If it is, just make a new batch of syrup.

Add your reserved grapefruit juice to the simple syrup and bring to a boil.  Then simmer for a few minutes to concentrate the flavor and thicken the syrup slightly.  Just like the candied grapefruit peel, this step is purely optional, but it will help ensure a moist cake.

Grapefruit Frosting

I made a batch of my basic American buttercream, but skipped the vanilla and the cream.  Then I beat in grapefruit juice one tablespoon at a time.  In total, I added 3 tablespoons of juice and it gave me a very mild citrus flavor.

Next time, I would suggest juicing 2 grapefruits and reducing the liquid down to a syrup.  That would concentrate the flavor and up the impact.  You could also add a teaspoon of zest, but I wanted a perfectly smooth frosting so that the buttercream ruffles would look nice.

Related Reading: Funfetti Cake with Fondant Ruffles

Grapefruit Cake

To get maximum flavor in my grapefruit cake, I used the juice and zest of one grapefruit.  I suggest juicing the fruit and then adding milk until you have one cup.  If your juice is slightly more or less than the recipe lists, just adjust your milk.

I creamed the butter and sugar with the grapefruit zest and vanilla to get the flavors started early in the process.  The final cake was slightly more bitter than I would have liked, so I have reduced the amount of zest in the recipe to just one tablespoon.  But you could always use the full amount!

Buttercream Ruffles Tutorial

Cake decorating is such a visual affair, I figured I should shoot a video of this for you!  Buttercream ruffles are actually quite easy to do, especially for beginner cake decorators.  All you need is a petal tip!  I used a #104, but you could use any sized petal tip for different looks.

But here are a few tips for success.  Only work with a small amount of frosting at a time.  As the buttercream warms in your hand the ruffles will get fatter and less delicate.  I also suggest wiping your tip off if you see excess frosting on the outside.  And try to get the ruffles to end at the same point up top.  

Enjoy!

This grapefruit cake is so easy to make, even with all of the different elements.  If you’re a huge citrus fan, you’re going to love this cake that is infused with grapefruit from top to bottom!  And if you’re a fan of Bakes & Blunders, follow me on Instagram for beautiful food pictures every week.

Print

Grapefruit Cake

Grapefruit infuses every part of this cake of a sweet and tangy explosion!

Pin this Recipe!

Course Dessert

Cuisine American

Keyword Birthday, Cake, Frosting

Prep Time 45 minutes minutes

Cook Time 1 hour hour 30 minutes minutes

Total Time 2 hours hours 15 minutes minutes

Servings 20 servings

Calories 523kcal

Author Colleen

Ingredients

Candied Grapefruit Peel & Grapefruit Simple Syrup

• 1 grapefruit
• 1 1/2 cups water
• 2 cups sugar divided

Grapefruit Frosting

• 1 lb unsalted butter room temperature
• 2 lbs powdered sugar sifted
• 1 Tbsp vanilla extract
• 2- 4 Tbsps grapefruit juice
• Pinch of salt
• Gel food color

Grapefruit Cake

• 8.5 oz all- purpose flour
• 2 oz cake flour
• 1/2 tsp salt
• 2 1/2 tsps baking powder
• 1/3 cup grapefruit juice
• 2/3 cup milk
• Gel food color
• 8 oz unsalted butter room temperature (2 sticks)
• 14 oz sugar
• 1/2 tsp vanilla
• 1 Tbsp grapefruit zest
• 4 eggs room temperature

Instructions

Candied Grapefruit Peel & Grapefruit Simple Syrup

• Slice off the peel of the grapefruit and cut into ¼ inch thick slices. Juice the grapefruit and set aside. Place the peel in a small saucepan and add enough water to cover by one inch. Bring to a boil and cook for 15 minutes. Drain and rinse with cold water.
• In the same saucepan, add 1 ½cups of water and 1 ½ cups of sugar to a boil. Add the grapefruit peel and simmer for 30 minutes, or until softened.
• Use a slotted spoon to scoop the grapefruit peel out of the syrup. Toss the peel with the remaining sugar and transfer to a baking sheet lined with wax paper. Let the peel dry for a day or two.
• With the remaining syrup, add the reserved grapefruit juice. Place the saucepan over medium heat and bring to a boil. Reduce the heat to low and simmer for 4 minutes. Let the syrup cool to room temperature. Store in an air tight container in the fridge.

Grapefruit Frosting

• Beat the butter on medium speed until pale and fluffy, about 3- 5 minutes. Scrape the bowl down as needed.
• Add a third of the powdered sugar and the vanilla to the bowl. Beat on low until combined, then on medium until creamy, about 1- 2 minutes. Scrape the bowl down.
• Add another third of the sugar and a tablespoon of juice to the bowl. Beat on low until combined, then on medium until creamy, about 1- 2 minutes. Scrape the bowl down.
• Add the remaining sugar and a pinch of salt to the bowl. Beat on low until combined, then on medium until creamy, about 1- 2 minutes. Scrape the bowl down.
• Add juice a little bit at a time, beating between additions, until the frosting reaches the right consistency. Add gel color and beat until combined.

Grapefruit Cake

• Preheat the oven to 350°F. Spray two 8 inch cake pans and line with parchment.
• In a medium bowl, sift together the flours, salt, and baking powder. Whisk to combine, then set aside. In a measuring glass, combine the juice, milk, and gel food color. Whisk to combine, then set aside.
• In a stand mixer, cream the butter, sugar, vanilla, and zest on a medium speed for about 5 minutes, or until light and fluffy. Scrape the bowl down.
• With the mixer on low, beat in the eggs one or two at a time. Beating between additions. Scrape the bowl down as needed.
• With the mixer still on low, add one third of the flour mixture. Once combined, drizzle in half of the liquid mixture. Scrape the bowl down and repeat the process. Scrape the bowl down again and add the final addition of flour. Mix until just nearly combined. Then fold the mixture with a spatula until combined.
• Divide the batter into the two pans and add cake strips (if using). Bake on the middle rack for 35- 40 minutes, or until the cakes spring back when poked. Cool in the pans for 10 minutes before inverting them onto a cooling rack to finish cooling.

Assembly

• Brush your cooled cakes liberally with the grapefruit simple syrup. Add a layer of frosting, then top with the second cake layer. Crumb coat and frost the cake as desired. Use the candied grapefruit peel as a topping, garnish, or place it between the layers.

My Favorite Products for this Recipe