Lemon Bar Cake

I’m swooning over this Lemon Bar Cake! It tastes just like lemon bars and incorporates every element of the bars in the cake — from the delicious shortbread crust to moist lemon cake layers and a tart lemon curd all topped with a beautifully sweet and smooth lemon buttercream.

Citrus is such a fun flavor to put in cake form! My Key Lime Pie Cake is bursting with lime flavor! Make sure to add it to your dessert menu! Another fun summer cake recipe is my Lemon Raspberry Cake!

I’m a converted cake lover. Let me explain. 🙂 Cakes were a big thing growing up, but I just wasn’t a fan! I would request cheesecake for my birthday instead. Cakes always seemed to be too dry, too sweet, not flavorful enough etc., etc. So yes, I’m a converted cake lover. Turns out I was eating the wrong kind of cakes!

For more insanely moist, perfectly sweet and super flavorful cakes, try my Coconut Cookies and Cream Cake, Biscoff Caramel Cake and my 7 Layer Bar Cake! If you are looking for another delicious cake to make in the springtime, then be sure to try my Carrot Cake with Pineapple and Pecans!

Why This Recipe Works

• Every element of a lemon bar represented. This lemon bar cake beautifully incorporates every element from a lemon bar! The shortbread crust under the cake is reminiscent of the shortbread crust on a lemon bar and the lemon curd paired with the lemon cake layers have the flavor and texture of the lemon curd part of the lemon bar. Can’t forget the sprinkle of powdered sugar you see on lemon bars! Say hello to the lemon buttercream! So light, fluffy and made with powdered sugar!
• Moist cake layers. If you aren’t a fan of cake because you’re used to dry cakes … you’re eating the wrong cakes! These lemon cake layers are so moist and flavorful! The lemon flavor comes out beautifully and thanks to the sour cream, buttermilk and vegetable oil, these cake layers are FAR from dry!
• Delicious balance of tart and sweet. I love how the tart lemon curd pairs so well with the sweet lemon buttercream!
• Only fresh lemon! That’s right, there isn’t any lemon extract in this cake! We only use fresh lemon juice and lemon zest to bring that beautifully fresh lemon flavor you love!

Ingredient Notes

For the Lemon Bar Cake

• Buttermilk: I love making cakes with buttermilk because I already know the flavor will taste better and the texture of the cake will be softer thanks to the buttermilk. 
• Sour Cream: Sour cream is high in fat, giving an extra boost of moisture to the cake. It also gives a depth of flavor with the bit of tart/tangy flavor. 
• Vegetable Oil: Using vegetable oil in cakes is important because vegetable oil is a liquid at room temperature. So when you cake is at room temperature, that oil in the cake keeps the cake moist. 
• Lemon Juice: I prefer freshly squeezed because you can taste a difference, but if you have the store bought already squeezed lemon juice that is fine too. 
• Eggs: You’ll need eggs for the cake and for the lemon curd. Extra yolks for the lemon curd will give you the texture you want (as well as that yellow color), but without the whites. Egg whites have the bulk of the eggy flavor, so remove as much of the whites from the 4 eggs as you can. 
• Lemon Zest: Using the lemon zest in addition to the lemon juice will give a sharper lemon flavor.
• Heavy Cream: Adding a bit of heavy cream to the lemon buttercream helps give an extra light lift to the texture since heavy cream gets light and fluffy when whipped. 

Step-by-Step Instructions

1. Make the shortbread crust. Prepare your cake pans following the recipe instructions. Make the shortbread crust and press it into the pans. Bake at 350º F for 11-13 minutes or until the edges are golden and the center start looking golden. Remove from the oven and let cool. 
2. Make the lemon cake layers. Whisk together the dry ingredients. Set aside. Beat the wet ingredients until well combined. With the mixer on low, add half of the dry ingredients and mix for about 30 seconds, then add the rest of the dry ingredients and mix just until no dry streaks remain. Don’t over mix. 
3. Divide the lemon cake batter evenly between three cake pans, pouring it on top of the slightly cooled shortbread crust. 
4. Bake for 30-40 minutes, or until a toothpick inserted in the center of the cake layer comes out with a couple moist crumbs stuck to it.
5. Remove the pans from the oven. When they have cooled enough to handle, flip the cakes out of the pans and onto a cooling rack to cool completely.

6. Make the lemon curd. Combine all the ingredients in a small saucepan and cook over medium heat, mixing continuously until the mixture has thickened enough to coat the back of a spoon.
7. Strain the mixture. Pour the curd through a fine mesh strainer into a storage container to ensure it is smooth and silky. Cover with plastic wrap and cool completely in the refrigerator.

8. Make the lemon buttercream. Beat the butter, salt, and lemon zest until smooth and light in texture and color. Add 3 cups of the powdered sugar and mix well. Add 2 tablespoons of lemon juice and the rest of the powdered sugar and beat for 2-3 minutes. Add 1 tablespoon of heavy cream and beat for about a minute.

9. Assemble the lemon bar cake. Place a cake layer, crust side down and spread a thin layer of lemon buttercream evenly over the top. Pipe a rim of buttercream around the top edge of the cake layer to create a dam. (See recipe tips). Add 1/2-2/3 cup lemon curd inside the buttercream dam.

10. Repeat with the second layer of cake, placing the second cake layer on top of the first layer. Place the third cake layer on top and crumb coat the entire cake in a thin layer of lemon buttercream. Refrigerate or freeze for a few minutes, until the buttercream is cold and no longer soft. Add the final layer of frosting around the entire cake.

• We used extra frosting to create a twisted rope border around the top of the cake and filled the center with extra lemon curd. Add additional decoration as desired.

Recipe Tips

Cake Tips

All cake pans and ovens are different so be sure to pay close attention to when your cakes are done baking. It may take shorter or longer than the time listed.

Using a serrated knife or cake leveler, cut the domed top off of each layer. This will ensure your cake is flat and even when assembled.

Covering the lemon curd with plastic wrap will help prevent a film-like top to form as it cools. This will keep the lemon curd nice and smooth while it cools. 

Place the first cake layer on a cake board or stand that has a small dollop of buttercream on it. This will help keep the cake from sliding around as you assemble it. 

Buttercream Tips

The frosting can be made a few days in advance and stored in the refrigerator. A few hours before cake assembly, set the frosting out at room temperature. Once the frosting has softened, beat in a stand mixer until smooth and spreadable.

Sift the 3 cups of powdered sugar into the butter mixture and scrape the sides of the bowl as needed. This will help your buttercream be nice and smooth!

Taste the buttercream as you go! If the lemon buttercream doesn’t taste lemony enough, add more lemon juice, one tablespoon at a time, until you’re happy with how it tastes. Just be sure to not add so much lemon juice that the frosting becomes runny and not able to hold its shape.

Add more heavy cream if the frosting is too thick to spread at room temperature.

Cake Assembly Tips/Cake Decorating Tips

Be sure to not overfill the cake as it will seep out when you add the next layer and make the cake unstable and difficult to finish icing. 

If your buttercream is too warm, decorating the cake will be difficult. The buttercream dam won’t hold the lemon curd in when another layer is placed on top. I’ve found that keeping my buttercream slightly colder than room temperature when I’m decorating a cake makes it the easiest to work with.

Make Ahead, Storing, and Freezing

If making the cakes ahead of time, wrap each layer in plastic wrap and freeze for up to four weeks. Let the cakes sit at room temperature for one hour before assembling the cake.

The lemon curd can be made 3-4 days in advance and stored in the fridge until it’s time to assemble the cake.

Store the lemon bar cake covered in the fridge for 3-5 days.

For more information on storing and freezing cakes, check out my How to Store and Freeze Cakes guide!

FAQs

More Lemon Recipes

• Lemon Jello Cake
• Lemon Poppy Seed Muffins
• Lemon Poppy Seed Bundt Cake
• Lemon Zucchini Bread
• Lemon Shortbread Cookies