This lemon blueberry cake is everything summer dreams are made of — bright, fresh, and packed with flavor in every single bite. The layers are wonderfully moist, and the combination of a tangy lemon buttercream with a rich blueberry reduction frosting makes it genuinely hard to stop at one slice. I’ve made this one more times than I can count, and it never disappoints.
Honestly, if blueberries hold a special place in your heart, this cake was made for you. The lemon spice and juice give it just the right amount of zing without being overpowering, and the two-buttercream approach — one batch infused with blueberry, the other pure lemon — takes the whole thing to another level. I kept mine as a naked cake, and I’d encourage you to do the same. The cake itself is so flavorful that heavy frosting would only get in the way.
Table of Contents
What You’ll Need to Make This
- Blueberries: Fresh blueberries work beautifully here, but frozen are perfectly fine too. Just make sure to thaw them completely, pat them dry, and toss with a little flour before using.
- Butter: Unsalted is my go-to, since salt levels vary between brands. Using unsalted butter lets you control the seasoning yourself. That said, salted butter works fine — just leave out any additional salt called for.
- Milk: Dairy-free? Swap in almond milk or soy milk without any issues.
- Sour Cream: This is what keeps the cake so tender and moist. Plain Greek yogurt is the best substitute if that’s what you have on hand.
- Egg Whites: Using only whites keeps the crumb lighter in both texture and color. If you’d rather use whole eggs, cut the sour cream in half to keep the balance right.
How to Make Lemon Blueberry Cake
Step 1: Heat your oven to 350°F and prep three 6-inch cake pans by buttering and flouring them well. Sift together the flour, baking powder, salt, and sugar into a large bowl and whisk to combine. In a smaller bowl, toss the blueberries and lemon zest with a tablespoon of the flour mixture.
Step 2: Whisk together all the wet ingredients — milk, sour cream, egg whites, lemon juice and zest, and vanilla — in a separate bowl. Set aside while you work on the next step.
Step 3: Using a stand mixer fitted with the paddle attachment, beat the butter for about two minutes until it looks light and creamy. Add the flour mixture and mix on low until it takes on a sandy texture. Keep the mixer running on low and slowly pour in the wet ingredients, mixing just until everything comes together. Fold in the blueberry mixture by hand with a spatula. Pour the batter evenly into your prepared pans and bake for 25 to 30 minutes, until the centers spring back when gently pressed. Flip onto a wire rack and let cool completely.
Step 4: For the blueberry reduction, combine the blueberries, water, lemon juice, and sugar in a small saucepan over medium heat. Let the berries burst, mash them down, then simmer until the mixture reduces by half. Strain it through a fine mesh sieve into a bowl and refrigerate until chilled.
Step 5: Beat the butter and salt together, then sift in the powdered sugar in two or three additions. Mix on low speed, drizzling in the lemon juice as you go. Scrape down the sides of the bowl and beat once more until everything is smooth and uniform.
Step 6: Scoop out about ¾ cup of the buttercream into a separate bowl. Stir in the chilled blueberry reduction one tablespoon at a time until you’re happy with the flavor and color.
Step 7: To fill the layers, pipe a thick border of the lemon buttercream around the edge of each layer, then spoon the blueberry buttercream into the center. This keeps the flavors distinct and prevents them from muddling together. Once stacked, frost the outside of the cake and smooth it out with an offset spatula.
Step 8: Finish with decorative dollops using an 846 piping tip. Tuck a few frozen blueberries inside each dollop if you’d like — the frosty coating on frozen berries adds a subtle sparkle that looks really lovely against the frosting.
Pro Tips for This Recipe
- Getting blueberries to stay suspended in cake batter instead of sinking to the bottom is easier than it sounds. Give them a quick toss in a tiny splash of lemon juice to slightly dampen the skin, then coat with a tablespoon of flour. When you pour the batter into your pans, take a moment to redistribute any berries that clump together — a simple nudge with a spoon does the trick.
- For those clean, flat layers you see in bakery-style cakes, try using cake strips. These are damp fabric bands wrapped around the outside of the pan before baking. They regulate the heat along the edges so the layers bake evenly and come out level without any doming or over-browning. You can find them online or make your own with strips of old towels. If you’re scaling up, double the recipe for 8-inch pans or triple it for 9-inch pans.
- When it comes to measuring flour, precision really matters here. Too much flour is the single most common reason cakes turn out dense. A kitchen scale is the most reliable option. If you don’t have one, fluff up the flour in its container first, lightly spoon it into your measuring cup, and level it off with a straight edge — never pack it down.
How To Store
Room Temperature: If your cake is unfrosted or you plan to serve it within the day, it can sit on the counter at room temperature for up to 24 hours. Just keep it covered with a cake dome or wrapped loosely in plastic wrap to prevent it from drying out.
Refrigerator: Because of the buttercream and blueberry reduction, this cake is best stored in the fridge. Place it in an airtight container or cover it well with plastic wrap and it will stay fresh for up to 5 days. Before serving, let it sit out at room temperature for 30 to 45 minutes — cold buttercream can taste a little dense, and bringing it back to room temp makes a noticeable difference in both flavor and texture.
Freezer: This cake freezes really well! You have two options here:
- Whole or sliced cake: Wrap individual slices or the entire cake tightly in plastic wrap, then again in foil or place in a freezer-safe bag. It will keep well for up to 3 months.
- Unfrosted cake layers: If you like to bake ahead, the plain cake layers freeze beautifully. Wrap each layer individually and freeze. When you’re ready to assemble, thaw them overnight in the fridge or for a couple of hours on the counter.
Lemon Blueberry Cake
Ingredients
For the Cake:
- ½ cup whole milk room temperature 120ml
- ½ cup sour cream room temperature 120g
- 3 egg whites room temperature
- 3 tablespoons fresh lemon juice
- 1 tablespoon lemon zest
- 1 tablespoon vanilla extract
- 2 cups all-purpose flour 240g
- 1⅔ cups granulated sugar 333g
- 1½ teaspoons baking powder
- ¼ teaspoon kosher salt
- ¾ cup unsalted butter room temperature 170g
- 1⅓ cups fresh blueberries 180g
For the Reduction:
- 1½ cups fresh blueberries 200g
- 1 tablespoon granulated sugar
- 1 tablespoon fresh lemon juice
- 1 tablespoon water
For the Lemon Buttercream:
- 1½ cups unsalted butter room temperature 340g
- ¼ teaspoon kosher salt
- 6 cups confectioners’ sugar 720g
- 3 tablespoons fresh lemon juice
Instructions
For the Cake:
- Preheat your oven to 350°F (175°C). Grease and lightly flour three 6-inch round cake pans. If you have cake strips, wrap them around the pans to help the cakes bake evenly.
- In a medium bowl, whisk together the milk, sour cream, egg whites, lemon juice, lemon zest, and vanilla until smooth. Set the mixture aside.
- In another bowl, sift together the flour, sugar, baking powder, and salt. Remove 1 tablespoon of the flour mixture and toss it with the blueberries to help keep them from sinking while baking.
- In a large mixing bowl, beat the softened butter until creamy. Add the remaining dry ingredients and mix on low speed until the mixture looks like fine crumbs or wet sand.
- Gradually pour the wet ingredients into the butter mixture while mixing on low speed. Mix just until combined, then beat for about 30 seconds until the batter is smooth and fluffy. Gently fold in the flour-coated blueberries with a spatula.
- Divide the batter evenly between the prepared cake pans, smoothing the tops with a spatula.
- Bake for about 30 minutes, or until the tops spring back when lightly touched or a toothpick inserted in the center comes out clean. Let the cakes cool in the pans for 15 minutes before transferring them to a wire rack to cool completely.
For the Reduction:
- Place ½ cup of the blueberries in the freezer while you prepare the sauce.
- In a small saucepan over medium-low heat, combine the remaining 1 cup blueberries, sugar, lemon juice, and water. Cook until the berries begin to burst, then gently mash them and simmer for a few minutes until the mixture has reduced by about half.
- Strain the blueberry mixture through a fine-mesh sieve into a small bowl, pressing to extract as much liquid as possible. Discard the solids, then refrigerate the blueberry reduction until you’re ready to use it.
For the Lemon Buttercream:
- Whip the butter: In a stand mixer fitted with the paddle attachment, beat the butter and salt on medium speed for about 3 minutes, until light and fluffy. Reduce the speed to low and gradually add the powdered sugar, scraping down the bowl as needed. Once combined, beat for another minute until smooth and creamy.
- Add the lemon: Mix in the lemon juice, one tablespoon at a time, until the buttercream reaches your preferred consistency and has a bright lemon flavor.
- Make the blueberry frosting: Scoop about 1 cup of the lemon buttercream into a separate bowl. Stir in the blueberry reduction, one tablespoon at a time, until you’re happy with the flavor and color.
- Fill the piping bags: Transfer the blueberry buttercream to a piping bag and snip off the tip. Spoon ½ cup of the lemon buttercream into a piping bag fitted with a decorative tip (846), then place the remaining lemon buttercream into a plain piping bag with the tip snipped off.
For the Assembly:
- Place one cake layer on a serving plate. Pipe a thick ring of lemon buttercream around the edge, then fill the center with the blueberry-lemon buttercream. Add the next cake layer and repeat.
- Cover the top and sides of the cake with lemon buttercream, smoothing it with an offset spatula. For a semi-naked finish, use a thinner layer on the sides and gently scrape away the excess.
- Pipe a ring of lemon buttercream dollops around the top edge of the cake, fill the center with frozen blueberries, and chill for 20 minutes before slicing and serving.
Notes
- Prep the blueberries: To keep the blueberries from sinking, lightly toss them with a little lemon juice, then coat them with about a tablespoon of flour. As you divide the batter between the pans, spread the berries out with a spoon so they’re evenly distributed instead of clumping together.
- Bake for even cake layers: For soft, evenly baked layers with light, straight edges, wrap damp cake strips around the outside of your cake pans before baking. They help the cakes bake more evenly from edge to center.
- Measure the flour the right way: For the best texture, measure your flour carefully. A kitchen scale is the most accurate option. If you’re using measuring cups, fluff the flour first, spoon it into the cup, and level it off with a knife instead of scooping directly from the bag.
- Decorate and save the extra frosting: If you’re making a naked cake, you’ll likely have some buttercream left over. Save it for frosting cupcakes or freeze it in an airtight container for another baking day.
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