Lemon Blueberry Sheet Cake with Lemon Glaze

This lemon blueberry sheet cake is the kind of easy dessert that disappears fast at potlucks and family dinners.

A tender, vanilla-scented crumb holds a riot of juicy blueberries, topped with a tangy lemon glaze that soaks right in. It bakes in a standard half-sheet pan to feed a crowd with minimal fuss.

Why This Lemon Blueberry Sheet Cake Works

The lemon hits you first, bright and zesty, then the blueberries burst through. The cake itself stays soft and tender, thanks to buttermilk and a good creaming step.

It’s a true one-pan wonder that bakes up in a sheet pan, so you get a big rectangle of cake with no fussy layering. The tangy glaze seeps into the warm cake, making every bite a little tart and a little sweet.

Ingredients

• 2 1/2 cups all-purpose flour: the backbone of a fluffy crumb
• 1 1/2 teaspoons baking powder: gives the cake its lift
• 1/2 teaspoon baking soda: helps create a tender texture
• 1/2 teaspoon fine sea salt: balances the sweetness
• 1/2 cup unsalted butter, softened: let it come to room temperature for easy creaming
• 1 1/2 cups granulated sugar: sweetens the cake and helps it brown
• 2 large eggs, at room temperature: bind everything together
• 1 tablespoon lemon zest: the source of that bright lemon flavor
• 1 teaspoon vanilla extract: rounds out the citrus
• 1 cup buttermilk, at room temperature: keeps the cake moist and tender
• 1 1/2 cups fresh blueberries: if using frozen, do not thaw
• 1 1/2 cups powdered sugar: for the tangy glaze
• 2 to 3 tablespoons fresh lemon juice: for the glaze, adjust to desired thickness
• Pinch of fine sea salt: for the glaze

Variations / Substitutions

• Swap the berries: raspberries or halved blackberries work beautifully here.
• Lime instead of lemon: use lime zest and juice for a different citrus twist.
• Almond extract: replace the vanilla with 1/4 teaspoon of almond extract for a subtle nutty note.
• Dairy-free: use a quality vegan butter and replace the buttermilk with 1 cup oat milk plus 1 tablespoon lemon juice.

For a smaller batch, our Classic Lemon Loaf hits all the same notes.

How to Make Lemon Blueberry Sheet Cake

Step 1: Mix the Dry Ingredients

Preheat the oven to 350°F (175°C) and grease a 13×18-inch half-sheet pan, lining the bottom with parchment paper if you like. Whisk the 2 1/2 cups flour, 1 1/2 teaspoons baking powder, 1/2 teaspoon baking soda, and 1/2 teaspoon salt together in a large bowl for about 30 seconds, until the mixture looks uniform and lump-free.

Getting the leavening agents evenly distributed now means no bitter pockets later. Set the bowl aside while you work on the wet ingredients.

Step 2: Cream the Butter and Sugar

In a stand mixer or a large bowl with a hand mixer, beat the 1/2 cup softened butter and 1 1/2 cups sugar on medium-high speed for a full 3 minutes. Stop when the mixture looks pale, light, and fluffy. Scrape down the sides, then beat in the 2 eggs one at a time, followed by the 1 tablespoon lemon zest and 1 teaspoon vanilla. The batter may look slightly curdled after adding the eggs; that’s completely fine.

This step builds the structure that keeps the cake tender. Rushing it will lead to a dense crumb, so give the butter and sugar real time to whip air into the mix.

Step 3: Fold the Wet and Dry Together

With the mixer on low, add the dry ingredients in three additions, alternating with the 1 cup buttermilk in two additions, starting and ending with the dry. Mix just until no dry streaks remain, about 20 to 30 seconds. Remove the bowl from the mixer and gently fold in the 1 1/2 cups blueberries with a spatula, being careful not to burst them.

The batter will be thick, pale yellow, and speckled with lemon zest and berries. A few floury patches are better than overmixing, which can make the cake tough.

Step 4: Bake the Cake

Scrape the batter into the prepared sheet pan and spread it into an even layer all the way to the corners. Bake on the center rack for 25 to 30 minutes, until a toothpick inserted in the middle comes out clean and the top springs back when you press it lightly. The edges will look golden and start to pull away from the sides.

Your kitchen will smell wonderful at this point. Let the cake cool in the pan on a wire rack for about 15 minutes before you glaze it—warm is perfect, piping hot will melt the glaze right off.

Step 5: Glaze and Slice the Cake

Whisk the 1 1/2 cups powdered sugar with 2 tablespoons of the lemon juice and a pinch of salt in a small bowl. Add more lemon juice a half-teaspoon at a time until the glaze is smooth and pourable but not watery. Drizzle it over the warm cake, letting it pool and spread naturally. Let the glaze set for about 10 minutes, then cut the cake into 24 squares and serve.

The glaze melts into the top, creating a crackly, tangy crust. Serve the squares while still slightly warm or at room temperature, and watch them disappear.

Tips for the Best Sheet Cake

• Toss fresh blueberries in a tablespoon of the measured flour before folding them in. That helps keep them suspended in the batter instead of sinking to the bottom.
• Make sure the butter, eggs, and buttermilk all come to room temperature before you start. Cold ingredients won’t cream properly and often lead to a heavy cake.
• Resist opening the oven door before the 25-minute mark. A rush of cool air can cause the cake to sink in the middle.
• If your blueberries are unusually large, the cake may need an extra 2 to 3 minutes in the oven.

Bake times by pan:

Storing the Cake

• Refrigerate: Keep the glazed cake loosely covered at room temperature for up to 2 days, or refrigerate it for up to 5 days. Bring it back to room temperature before serving for the softest texture.
• Freeze: The unglazed cake freezes beautifully. Wrap it tightly and freeze up to 3 months. Thaw overnight on the counter, then glaze fresh.

Frequently Asked Questions

Can I use frozen blueberries?

Yes, you can use them straight from the freezer. Do not thaw them, or they’ll bleed and turn the batter purple. Toss them with a little extra flour to help prevent sinking.

Can I make this cake ahead of time?

Absolutely. Bake the cake up to 24 hours in advance, keep it covered, and glaze it a few hours before serving. The glaze will stay fresh and glossy.

What can I substitute for buttermilk?

Mix 1 cup of whole milk with 1 tablespoon of lemon juice or white vinegar. Let it sit for 5 minutes until it curdles slightly, then use it in place of the buttermilk.

Why did my cake turn out dense?

Overmixing after adding the flour or using cold butter are the most common reasons. Cream the butter and sugar until genuinely fluffy, and mix the batter as gently as possible once the dry ingredients go in.

Lemon Blueberry Sheet Cake Recipe

Print Recipe Pin Recipe

Prep Time 15 minutes mins

Cook Time 30 minutes mins

Total Time 45 minutes mins

Servings: 24 servings

Calories: 180

Ingredients Method Notes

Ingredients

  

• 2 1/2 cups all-purpose flour
• 1 1/2 teaspoons baking powder
• 1/2 teaspoon baking soda
• 1/2 teaspoon fine sea salt
• 1/2 cup unsalted butter, softened
• 1 1/2 cups granulated sugar
• 2 large eggs, at room temperature
• 1 tablespoon lemon zest
• 1 teaspoon vanilla extract
• 1 cup buttermilk, at room temperature
• 1 1/2 cups fresh blueberries
• 1 1/2 cups powdered sugar
• 2 to 3 tablespoons fresh lemon juice
• Pinch of fine sea salt

Method

 

1. Preheat oven to 350°F (175°C). Grease a 13×18-inch half-sheet pan. Whisk flour, baking powder, baking soda, and salt in a bowl.
2. Beat butter and sugar for 3 minutes until pale and fluffy. Beat in eggs, lemon zest, and vanilla.
3. Alternate adding dry mix and buttermilk, starting and ending with dry. Fold in blueberries gently.
4. Spread batter in pan. Bake 25-30 minutes, until a toothpick comes out clean. Cool 15 minutes.
5. Whisk powdered sugar, 2 tablespoons lemon juice, and salt into a smooth glaze. Drizzle over warm cake. Let set 10 minutes, then slice into 24 squares.

Notes

If the glaze feels too thick, thin it with more lemon juice a half-teaspoon at a time. For a thicker, frosting-like spread, use less liquid and smooth it on with a spatula.