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This easy lemon sheet cake is bursting with bright, citrusy flavor from fresh lemon juice and zest in both the fluffy cake and zippy buttercream frosting. This one-layer version of my lemon cake is moist, flavorful, and perfect for feeding a crowd– no layering or fancy tools required.

Someone is using a spatula to lift a slice of lemon sheet cake out of a baking pan.

THE PERFECT SHEET CAKE FOR THE LEMON LOVERS

If you’ve tried my lemon curd cake, a stacked lemon cake with fresh lemon curd between the layers, then you already know this sheet cake is going to rock your lemon-loving socks. This carefully tested recipe produces a cake that is soft, fluffy, and full of fresh lemon flavor in every bite. This cake is made with fresh lemon juice and fresh lemon zest in the cake as well as the frosting, and we lean into my best tip for infusing citrus into baked goods to really draw out the maximum flavor possible (we’ll get there).

While I paired this lemon cake with a simple lemon buttercream, you can choose any frosting that feels just right (we’ll get to that one, too). What you can be sure of, though, is that the simplicity of a 9″ x 13″ pan turns everything folks love about my lemon layer cake into a fuss-free dessert that’s perfect for parties or entertaining without all the fuss or sacrifice of flavor. Easy, crowd-friendly, and still some wiggle room for creativity? Sign me up for a bite every time!

Aerial photo of a slice of lemon sheet cake on a plate with a fork.

Aerial photo of a lemon sheet cake sliced and sitting in a baking pan.

WHAT YOU’LL NEED

You only need 10 ingredients, and you’ll share a lot of them between the cake and the frosting.

Aerial photo of the ingredients to make lemon sheet cake with text overlay labeling each ingredient.

For the cake: you’ll need all-purpose flour, baking powder, salt, unsalted butter, granulated sugar, lemons, eggs, vanilla extract, and milk.

For the frosting: you’ll need more unsalted butter, more lemons, powdered sugar, and vanilla extract and salt again.

KEY INGREDIENT NOTES

FRESH LEMON JUICE & ZEST: do not be tempted to use jarred lemon juice for this cake, as lemon is the star of the show and we can’t risk it not tasting like actual, fresh lemons. You’ll need approximately 3 lemons for ½ cup of lemon juice, and you’ll need a couple additional Tablespoons for the frosting, so I suggest 4 lemons. You’ll use the zest of 3 of the lemons between the cake and the frosting, and you can garnish the cake with the 4th lemon, if you prefer.

MILK: while buttermilk is often used in cakes where we want to retain moisture, the addition of the lemon juice mimics the same characteristics, so it’s almost as if we really are using buttermilk for this cake. Buttermilk is often low in fat, but I recommend whole cow milk for this cake, which brings maximum creaminess to the crumb.

For best results, use a zester & juicer: this is my favorite citrus zester which gets zest nice and small. My favorite citrus juicer is one that has graduations for measuring and a way to catch the seeds.

A slice of lemon sheet cake with a bite taken out of it with a fork.

HOW TO MAKE LEMON SHEET CAKE

This cake is really simple to make, but I have some key steps you’ll want to pay close attention to in order to get the best results out of your methods.

Combine the dry ingredients: start by tossing together the flour, baking powder, and salt, then set this mixture aside.

Cream the butter/sugar/zest + make the wet ingredient base: next beat the butter, sugar, and lemon zest on medium-high speed until light and fluffy, then add each egg, one at a time, beating on medium-high speed until fully incorporated. Don’t forget to scrape down the sides as necessary. Lastly, add the vanilla extract and beat again until it is combined.

Sugar, butter, and lemon zest in a large glass mixing bowl.

A spatula with creamed butter and sugar with lemon zest on it.

Creaming the zest into the butter and sugar infuses the lemon flavor into the cake more effectively than just adding it to the wet ingredients.

Sour the milk: stir the lemon juice into the milk, then scrape down the sides of the mixer bowl and turn the mixer speed to low.

Alternate dry ingredients with the soured milk/buttermilk: this is another crucial step. You’ll split your dry ingredients into roughly 3 parts (just eyeball this, it doesn’t have to be perfect) and your buttermilk/vinegar + milk in half (again, eyeball), then, starting with the dry ingredients, alternate adding each to the batter and letting it slowly incorporate.

Why are we alternating wet and dry ingredients? Rather than adding everything all at once, we want to keep the integrity of the cake batter without overloading it with too many dry ingredients to find places for nor do we want to drown it in liquid. By adding some of the dry ingredients first, we give the liquid somewhere to go and absorb into, which keeps the batter nice and smooth and avoids flooding it or creating lumps.

This is a step I use in delicate cake batters that seems silly but really does yield flawless results. Again, don’t worry about splitting these into perfect proportions. Trust your eyeballs to guide you.

Aerial photo of a bowl of lemon cake batter with a spatula.

Aerial photo of lemon sheet cake batter in a baking sheet.

Bake the cake: this is a quick bake, but you’ll want to make sure the cake is completely cool before you add the frosting. I typically make my frosting while the cake bakes/cools, but you can do it whenever makes sense for you. You can also cover the cooled cake and frost it a day layer, which is what I typically do.

TOP WITH CREAMY LEMON BUTTERCREAM

While I love the simplicity of the lemon buttercream, I love leaning into the tanginess of cream cheese frosting with my lemon curd cake recipe (add some lemon zest to make lemon cream cheese frosting). You can use anything from vanilla buttercream to Swiss meringue buttercream. One I’ve never tried but feel like I should is strawberry buttercream. A strawberry lemonade type of situation, if you will… And invite me over for a taste, please?