Lemon Buttermilk Cake with Blueberry Jam Filling

Looking for a simple summertime cake with fresh and bold flavors? Learn how to make this delicious lemon blueberry cake. 

This cake is made with fluffy layers of lemon buttermilk cake that’s filled with blueberry jam and zesty lemon buttercream. 

In this tutorial, you’ll learn how to make lemon buttermilk cake layers from scratch. This cake recipe is an excellent staple for any new baker. You can easily swap the lemon juice and zest for another citrus like grapefruit, lime, or orange to create more delicious cakes.  

Then we’ll talk about how to make homemade blueberry jam that’s sweet and tart. This jam is so good you can eat it with anything, seriously enjoy a spoonful so good! 

The cake is complete with creamy lemon buttercream made with a lemon gel for a concentrated lemon flavor. The lemon gel made with lemon juice, cornstarch, and zest, is quick to make and won’t water down the buttercream while serving bold flavors. 

I’ll show you how to decorate this cake with a star tip to create a cool texture on the sides of the cake. 

This lemon blueberry cake celebrates the beauty of fresh summer fruit. I’m so excited to share this cake with you!  

Tips for Success: 

• Read through the ingredients and instructions to get a better idea of how much time and what you need to make this cake.
• A single batch of this cake recipe makes three, 6-inch round cake layers or two 8-inch round cake layers. Double the cake recipe to make enough cake batter for three, 8-inch cake layers.
• In this cake recipe, you need ⅔ cup buttermilk; if you don’t have any buttermilk on hand, you can easily use ⅔ cup whole milk mixed with 2 ½ teaspoon lemon juice or white vinegar to make your own. 
• To make cake flour at home, mix 2 ¾ cups all-purpose flour and ¼ cup cornstarch. Sift or whisk together to get rid of any lumps. 
• Be careful not to overmix this cake batter, or else the cake will come out dense. Mix until all ingredients are well incorporated.
• You can bake the cake layers ahead of time. Wrap the cake layers in plastic wrap and freeze up to one month. 
• You can make the lemon buttercream and blueberry jam filling a day ahead and refrigerate them overnight. Then take them out to come back to room temperature. Make sure the buttercream is at room temperature before re-whipping.
• Serve at room temperature and enjoy! 

What Tools You’ll Need to Make This Cake: 

• 5-quart, Stand Mixer with mixing bowl & paddle attachment
• 3, 6-inch cake pans or 2, 8-inch cake pans
• Offset spatula 
• 8-inch or 10-inch white cake board 
• Serrated knife or cake leveler 
• Turntable 
• Cake scraper or bench scraper
• Whisk or sifter
• Rubber Spatula
• Non-Stick Cooking Spray and Parchment Paper
• Ice Cream Scooper with Trigger Release (for dividing cake batter evenly)
• Piping Bags (I use reusable silicone bags)
• Ateco #844 Star Tip
• Cake Stand, optional

Here’s how to make this lemon buttermilk cake with blueberry jam filling! 

Let’s Get Baking! 

How to Make Lemon Buttermilk Cake Layers

1. Preheat the oven to 325 °F. Spray three 6-inch round cake pans with a non-stick spray and line the bottom of each pan with parchment paper.
2. In a medium-size bowl, whisk and stir together the cake flour, baking powder, and salt. Set aside. 
3. In the stand mixer bowl fitted with a paddle attachment, beat the butter, sugar, and oil on medium-high for 5 minutes.
4. Add the eggs, one at a time to the stand mixer bowl and beat on medium until well incorporated.
5. Turn the mixer on low, add the flour mixture, followed by the buttermilk.  
6. Pour in lemon juice, vanilla, and zest. Mix on medium for another 30 seconds then scrape down the sides of the bowl. 
7. Evenly distribute the cake batter among the three cake pans and bake for about 35-45 minutes or until a toothpick inserted into the center of each cake comes out clean or with just a few moist crumbs.
8. Remove cakes from the oven and let cool in pans for 10 minutes before inverting onto cooling racks to cool completely — wrap cakes in plastic wrap and place in the freezer to chill for at least 30 minutes. 

How to Make Blueberry Jam Filling 

1. In a medium saucepan, mix the blueberries and sugar. Continue mixing with a rubber spatula over low-medium heat until the sugar has dissolved and the berries begin to boil.
2. In a small bowl, combine the cornstarch and water. Add cornstarch mixture to the boiling berries and continue to stir with a rubber spatula. 
3. Continue cooking the mixture for 2-3 minutes until it is thickened and coats the back of a spatula. Remove from heat and add lemon juice. 
4. Pour the blueberry filling into a small bowl to cool. Press plastic wrap directly onto the surface to prevent a skin from forming. Set aside to fully cool. 

How to Make Lemon Gel for Lemon Buttercream 

1. In a small saucepot, whisk together lemon juice and cornstarch. Place the pot over medium heat for 2-5 minutes to bring to a boil, stir with a rubber spatula constantly to prevent it from burning on the bottom. 
2. Add lemon zest to the mixture. The lemon should be opaque and thick. Once thick, remove from the heat and place into the freezer to cool quickly. 

Creamy and Tangy Lemon Buttercream 

1. In the stand mixer bowl fitted with the paddle attachment, beat the butter until light and fluffy, about 2 minutes.
2. Turn the mixer to low and add the cold lemon gel, salt, and vanilla. 
3. Next, gradually add powdered sugar, followed by the heavy cream. Mix on medium-high speed for about 5 minutes, until light and fluffy. Scrape down the sides of the bowl. 
4. Place the buttercream into a piping bag fitted with #844 star tip. 
5. Before using, turn the mixer on low and mix for 2 minutes to push out any air bubbles or use a rubber spatula to push out the air bubbles. (You may need to repeat this step when frosting the outside of the cake). 

Putting It All Together

1. Remove the lemon cake layers from the freezer and unwrap the cake layers. Next, use a serrated knife to cut off the cakes’ dome to make the layers flat and even. 
2. Add a small amount of buttercream onto the center of the cake board.
3. Layer a chilled lemon cake, cut side up onto the cake board. Place a thin layer of buttercream on top of the cake then pipe two rings of buttercream stacked on top of one another. Add 1/4 cup of blueberry jam inside the ring of buttercream. 
4. Place another cake layer cut side down over the top. Repeat the process for another layer—Crumb coat and freeze for 30 minutes. 
5. Next, fill a piping bag that’s fitted with a #844 star tip with lemon buttercream. 
6. On the frozen cake, start from the bottom while spinning the cake, squeeze consistent pressure on the piping bag, and pipe a row around the cake. Then pipe another row directly on top of the previous row. Make sure to line up the starting point for a straight seam in the back of the cake. 
7. Repeat this process all over the sides of the cake. 
8. Then with the same piping bag and tip pipe, a rope border on top of the cake, leaving the center open. 
9. Finally, fill in the top of the cake with blueberry jam. 
10. Serve at room temperature and enjoy! 

You May Also Enjoy: 

• Lemon Blueberry Thyme Cake (recipe)
• Jumbo Lemon Blueberry Muffins with Brown Sugar Crumble (recipe) 
• How to Decorate Your First Cake (free course)
• Cake Decorating Tool Kit (24-piece kit with free shipping) 
• Cake Decorating Creator Program (ultimate bundle)

This cake is perfect for summertime parties like garden parties, birthdays, and even an inmate wedding. The technique you learn here will help you gain confidence in the kitchen so you can take on any cake challenge! 

Are you struggling with cake decorating and need more one on one help? I’m now offering an online cake course called Cake Decorating for Beginners. This cake course will teach you everything you need to know to make beautiful cakes at home. You’ll get video and written tutorials so you can have the best experience!

It doesn’t matter if you are brand new to baking or have dabbled in decorating cake before; this Cake Decorating for Beginners Course will help you. My promise to you is if I could do this, then you can do this too! CLICK HERE TO ENROLL 

Please let me know if you have any questions, email me here at xokatierosario@gmail.com, and I’ll be happy to help! I can’t wait to see your cake! 

Happy Decorating! 

Watch The How-to Video Below: 

Hey, if you liked this tutorial, you really should check out, Cake Decorating Creator Program, my online cake course. I coach you on everything I teach on these cake tutorials so that you can uplevel your baking and decorating skills. We 10x it so you get the results you want most. Like any new skill, it’s important to learn from the ground up to build a foundation, so take on any cake challenge. It is an investment your future self will thank you for. Check it out at XOKatieRosario.com/online-cake-course. I will see you there.

 

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