For fellow lemon enthusiasts, prepare to fall in love with this effortlessly delicious lemon sheet cake recipe! Crafted with the vibrant zest and juice of fresh lemons, rich buttermilk, and a touch of tangy sour cream, this recipe elevates a simple box of cake mix into an extraordinarily moist and intensely flavorful dessert. Crowned with a luxurious lemon buttercream, it’s a guaranteed crowd-pleaser and my top choice for any warm-weather celebration or casual gathering.

Calling all lemon lovers! I’ve taken all the best qualities of my favorite lemon cupcakes and transformed them into a magnificent sheet cake, perfect for serving a large group. Whether it’s a holiday feast, a casual potluck, or a cherished summertime occasion, this cake is designed to impress with minimal fuss. We start with a convenient box of vanilla cake mix, which serves as a fantastic foundation. But don’t let the convenience fool you – we’re enhancing it significantly with fresh lemon juice, rich buttermilk, and creamy sour cream. These additions ensure an incredibly moist, tender, and truly delicious lemon sheet cake that tastes completely homemade.

To complement the bright cake, I’ve chosen a decadent lemon buttercream frosting. This frosting is not just sweet; it carries a delightful tang that perfectly balances the cake’s sweetness. If you’re looking for an alternative, you can certainly use the lighter lemon whipped cream frosting I use for my lemon cupcakes. Either choice will create a phenomenal dessert. The best part? This entire recipe comes together with just a handful of key ingredients, making it remarkably simple to execute.

Lemon Sheet Cake Recipe

Craft this bright and zesty lemon sheet cake with luscious buttercream frosting in under an hour, starting with a convenient box of cake mix. The secret to its irresistible taste lies in generous amounts of real lemon juice and zest!

Prep:
20 minutes

Cook:
27 minutes

Total Time:
47 minutes

Servings:
24 slices

Ingredients

For the Cake

• 26.5 ounces vanilla cake mix (typically 2 standard 13.25-ounce boxes)
• 1 cup unsalted butter, melted (2 sticks)
• 4 large eggs, at room temperature
• ½ cup sour cream, at room temperature
• ⅔ cup buttermilk, at room temperature
• ⅓ cup freshly squeezed lemon juice (from about 3 lemons)
• 2 tablespoons lemon zest (from 2 lemons)

For the Lemon Buttercream Frosting

• 5 cups powdered sugar (confectioners’ sugar)
• 1½ cups unsalted butter, slightly softened (3 sticks)
• ⅓ cup freshly squeezed lemon juice (from about 3 lemons)
• 1 teaspoon lemon zest (from 1 lemon)

Equipment

• Kitchen Scale (optional, for precise cake mix measurement)
• 13×18-inch Rimmed Baking Sheet
• Electric Hand Mixer or Stand Mixer
• Parchment Paper
• Spatula

Instructions

1. Prepare Your Pan: Preheat your oven to 350°F (175°C). Line a 13×18-inch baking sheet with parchment paper, allowing it to extend slightly higher than the sides of the pan; this will make lifting the finished cake easier. Lightly spray the parchment paper with nonstick cooking spray, then set the prepared pan aside.

2. Mix the Cake Batter: In a large mixing bowl, combine the vanilla cake mix, melted unsalted butter, large eggs, sour cream, buttermilk, freshly squeezed lemon juice, and lemon zest. Beat with an electric hand mixer or stand mixer on medium speed until all ingredients are well combined and the batter is smooth. Do not overmix.

   

3. Spread the Batter: Pour the prepared cake batter evenly onto the parchment-lined baking sheet. Use a spatula to gently spread the batter to all corners, ensuring an even layer for consistent baking.

   

4. Bake the Cake: Place the baking sheet into the preheated oven and bake for 27-28 minutes. The cake is done when a toothpick inserted into the center comes out clean or with moist crumbs attached. Avoid overbaking to maintain moisture.

   

5. Cool Completely: Once baked, remove the cake from the oven and transfer the pan to a wire rack to cool completely. It’s crucial for the cake to be entirely cool before applying frosting to prevent melting.

6. Prepare the Lemon Buttercream: While the cake cools, begin making the frosting. In a large bowl, combine the powdered sugar, slightly softened unsalted butter, freshly squeezed lemon juice, and lemon zest. Beat on low speed until the ingredients are just combined, then increase the speed to high. Beat for approximately 5 minutes, or until the frosting becomes wonderfully light, fluffy, and smooth. If the frosting appears too thick, beat in an additional tablespoon of lemon juice until the desired consistency is achieved.

   

7. Frost and Decorate: Once the cake is completely cool, spread an even layer of the lemon buttercream frosting over the top. Decorate as desired; fresh berries, additional lemon zest, or thin lemon slices make beautiful and tasty garnishes.

   

Notes & Tips for Success

• Batter Consistency: When combining the lemon juice, buttermilk, and sour cream with the cake mix, you might notice the batter looking slightly curdled. Don’t worry, this is completely normal due to the acidic ingredients interacting with the dairy, and it will not negatively impact the final texture or flavor of your baked cake.
• Boosting Lemon Flavor: The natural flavor compounds in lemons can be somewhat delicate and may diminish slightly during baking. While this recipe includes a generous amount of fresh juice and zest, if you desire an even more pronounced lemon punch, consider adding ½ to 1 teaspoon of pure lemon extract to the cake batter.
• Moisture Balance is Key: It’s tempting to add more lemon juice to the cake batter for extra flavor, but resist this urge! Excessive liquid can disrupt the delicate balance of the batter, leading to a cake that is too dense or even collapses in the oven. Stick to the specified amounts for the perfect moist crumb.
• Citrus Variations: This versatile recipe is incredibly adaptable to almost any citrus fruit! Feel free to experiment by swapping lemons for limes, oranges, grapefruits, clementines, Meyer lemons, key limes, or even pomelos. For a fun visual twist and unique flavor, try using blood oranges or cara cara oranges in both the cake and frosting.

Layer Cake Adaptation: To transform this sheet cake recipe into an elegant layer cake, you have a couple of options. You can either bake the sheet cake as instructed and then carefully cut out round layers using a cake ring or knife, or you can directly pour the batter into two or three round cake pans. For 8-inch or 9-inch round pans, fill them no more than halfway. Adjust baking time to approximately 30-35 minutes, or until a toothpick comes out clean. Ensure pans are well-greased and floured, or lined with parchment circles.

Storage Recommendations: Keep your frosted lemon sheet cake fresh by storing it in an airtight container. It can be kept at room temperature for up to 3 days, in the refrigerator for up to 5 days, or frozen for up to 3 months. If freezing, wrap slices or the whole cake tightly in plastic wrap and then aluminum foil. Thaw frozen cake overnight in the refrigerator before serving chilled or at room temperature.

Nutrition Facts

Lemon Sheet Cake Recipe

Amount Per Serving (1 slice)

Calories 411
Calories from Fat 198

% Daily Value*

Fat 22g34%

Saturated Fat 14g88%

Trans Fat 1g

Polyunsaturated Fat 1g

Monounsaturated Fat 6g

Cholesterol 85mg28%

Sodium 240mg10%

Potassium 60mg2%

Carbohydrates 52g17%

Fiber 0.4g2%

Sugar 38g42%

Protein 3g6%

Vitamin A 677IU14%

Vitamin C 3mg4%

Calcium 93mg9%

Iron 1mg6%

* Percent Daily Values are based on a 2000 calorie diet.

Author:
Becky Hardin

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How to Make this Easy Lemon Sheet Cake: A Step-by-Step Guide

This recipe transforms a basic vanilla cake mix into a gourmet-tasting lemon sheet cake with incredible ease. Follow these simple steps for a dessert that’s bursting with citrus flavor and perfect for any occasion.

Step 1: Prepare Your Batter. Begin by preheating your oven to 350°F (175°C). Line a 13×18-inch rimmed baking sheet with parchment paper, allowing it to hang over the edges slightly for easy removal of the finished cake. Lightly spray the parchment with nonstick cooking spray. In a large mixing bowl, combine the 26.5 ounces (two standard boxes) of vanilla cake mix, 1 cup of melted unsalted butter, 4 large room-temperature eggs, ½ cup of room-temperature sour cream, ⅔ cup of room-temperature buttermilk, ⅓ cup of freshly squeezed lemon juice, and 2 tablespoons of fresh lemon zest. Beat until just combined and smooth, taking care not to overmix the batter. This careful combination of ingredients ensures a moist and tender crumb.

Step 2: Spread Evenly in the Pan. Once your batter is mixed, carefully pour it onto the prepared baking sheet. Using a rubber spatula or an offset spatula, gently spread the batter out to create an even layer across the entire surface of the pan. This is crucial for uniform baking and ensuring every slice has the perfect thickness.

Step 3: Bake to Perfection. Transfer the baking sheet to your preheated oven. Bake the lemon sheet cake for approximately 27-28 minutes. You’ll know it’s perfectly baked when a wooden toothpick inserted into the center of the cake comes out clean or with just a few moist crumbs attached. Be mindful not to overbake, as this can lead to a dry cake. Once baked, remove the cake from the oven and place the entire pan on a wire rack to cool completely. Allowing it to cool fully is vital before you move on to frosting.

Step 4: Craft the Luscious Lemon Buttercream. While your cake is cooling, prepare the star of the show – the lemon buttercream frosting. In a large mixing bowl, combine 5 cups of powdered sugar, 1½ cups of slightly softened unsalted butter, ⅓ cup of freshly squeezed lemon juice, and 1 teaspoon of fresh lemon zest. Start by beating these ingredients on low speed with an electric mixer until they are just incorporated. Then, increase the speed to high and beat vigorously for about 5 minutes. The goal is a light, airy, and incredibly fluffy frosting. If you find your frosting to be a little too stiff, simply beat in an additional tablespoon of lemon juice, one teaspoon at a time, until you reach your desired spreadable consistency.

Step 5: Frost and Garnish Your Masterpiece. Once the cake has cooled completely (this is important!), gently spread an even, generous layer of your tangy lemon buttercream frosting over the entire surface of the sheet cake. Now comes the fun part: decoration! I love to add a fresh, summery touch with vibrant mixed berries, such as raspberries, blueberries, and sliced strawberries, along with thin, elegant slices of fresh lemon. These garnishes not only add a pop of color but also enhance the overall fresh flavor of the cake, making it truly irresistible.

Frequently Asked Questions About Lemon Sheet Cake

Can I make this lemon sheet cake ahead of time?

Absolutely! This lemon sheet cake is fantastic for making in advance. You can bake the cake a day or two before you plan to serve it. Once baked and cooled, wrap it tightly in plastic wrap and store at room temperature. Prepare the buttercream separately and store it in an airtight container in the refrigerator. When you’re ready to serve, simply re-whip the frosting for a minute or two to restore its fluffiness, then frost and decorate the cooled cake. This makes entertaining a breeze!

What’s the best way to get room temperature ingredients quickly?

Many baking recipes, including this one, call for room temperature ingredients like eggs, butter, buttermilk, and sour cream because they emulsify more easily, leading to a smoother batter and a more uniform, tender cake. To quickly bring eggs to room temperature, place them in a bowl of warm water for 5-10 minutes. For butter, cut it into smaller cubes and let it sit on the counter for about 30 minutes, or gently microwave for a few seconds (being careful not to melt it completely). Buttermilk and sour cream can be warmed gently in the microwave for 10-15 seconds, or let them sit on the counter for 30 minutes to an hour.

Why is my lemon cake dense or dry?

A dense or dry lemon cake can usually be attributed to a few factors. Overmixing the batter is a common culprit; it develops the gluten too much, leading to a tough texture. Overbaking is another major cause of dryness, as it removes too much moisture from the cake. Always rely on the toothpick test and keep a close eye on your oven. Ensure your ingredients are at room temperature as specified, which helps create a smoother, more aerified batter. Lastly, make sure your baking soda/powder (if applicable to the cake mix used, or if adding extra) is fresh and active.

Can I use bottled lemon juice?

While fresh lemon juice and zest are highly recommended for the best, brightest, and most authentic lemon flavor, you can use bottled lemon juice in a pinch. However, be aware that the flavor will not be as vibrant or nuanced. If you must use bottled juice, consider adding an extra teaspoon of lemon zest (using fresh lemons for just the zest) or a touch of pure lemon extract to compensate for the difference in flavor intensity. The zest carries much of the essential lemon oils that contribute to a truly aromatic cake.

How to Store and Enjoy Your Lemon Sheet Cake

Proper storage is key to keeping your delicious lemon sheet cake fresh and moist for as long as possible. Once frosted, store your lemon sheet cake in an airtight container to prevent it from drying out. At room temperature, it will stay fresh and delicious for up to 3 days. If you need to keep it longer, transfer it to the refrigerator, where it will last for up to 5 days. For extended storage, slices of the cake (or the entire cake, if wrapped well) can be frozen for up to 3 months. To freeze, wrap individual slices tightly in plastic wrap, then an additional layer of aluminum foil. When ready to enjoy, simply let it thaw overnight in the refrigerator, then bring to room temperature before serving for the best texture and flavor.