This lemon and blueberry cake has four mouthwatering elements:
zesty lemon cake
tangy lemon curd filling
sweet blueberry buttercream
juicy fresh blueberries
The combination is irresistible!
How to make this Lemon and Blueberry Cake
Make sure all of your refrigerated ingredients are at room temperature before you begin.
Start by creaming the butter and sugar together, which takes about three minutes. Meanwhile, zest your lemons. Using a lemon zester is ideal because it only takes off the fragrant outer peel instead of the bitter white pith underneath. If you don’t have a zester you can use the fine side of a grater.
By now the butter and sugar should be pale and creamy. Add the lemon zest and mix it in and then crack your eggs and add these one by one. Mix for about 30 seconds after each one so that they incorporate properly.
Now add the vanilla and mix that in. In a bowl, whisk together the flour and baking powder. Add half of this to the mixing bowl, mixing only until it’s just combined. As soon as you don't see any flour in the batter anymore, turn the mixer off. Avoiding over-mixing prevents a tough, dense cake. Then add the milk and sour cream and mix those in. If you need a substitute, instead of milk and sour cream you can use the same amount of buttermilk. Finally, mix in the rest of the flour mixture. Your batter should be quite runny and pale in colour with little flecks of yellow lemon zest.
Divide the lemon cake batter between three greased baking pans. Don't worry - we'll add the blueberry soon! Tap the pans to level them or spread the batter flat with a spatula. The recipe listed below makes a three-layer 6" cake or you can double it for a three-layer 8" cake. For mini cakes, use the 6" batter to make four 4" cakes. Or of course, you can divide the recipe by four to make just one 4" cake.
Bake the cake layers at 325F or 160C for 30 minutes. The cakes are baked when they don’t wiggle in the middle when you jiggle the pan. A toothpick poked into the middle of each cake will come out clean.
Run a spatula gently around the edges of each pan to loosen the cakes. Let the cakes cool completely before you assemble your cake.
A quick side note on substitutions. As I mentioned earlier you can use buttermilk instead of the milk and sour cream. For example, instead of 1/2 cup sour cream and 1/2 cup of milk, use 1 cup of buttermilk. Although I prefer the flavour and texture of this cake with sour cream, the buttermilk version is very similar! Both are soft and light but rich and buttery, too.
How to make lemon curd for this Lemon and Blueberry Cake
To make this cake even more lemony we’re going to make lemon curd. You’ll need lemon juice, lemon zest, butter, sugar, and eggs.
To prepare the ingredients, crack the eggs and cut your butter into small pieces so that it will melt easily. Zest your lemons and then squeeze them to measure out the lemon juice.
Put all of the ingredients into a small saucepan and heat over a low heat. The key to smooth lemon curd is to heat it very very gently so that the eggs don’t cook too fast and make the curd lumpy. It will take about 30 minutes to cook this and you need to whisk it as it cooks. Listen to a good playlist or podcast and don’t turn that heat up! You’ll notice the curd thicken as it cooks. To test if it's ready, dip a spoon into it and check the back of the spoon. It should be covered in a layer of curd that doesn't run off the spoon. If you wipe your finger through it, it will leave a clear trail.
Pour the curd through a sieve and then cover it with plastic wrap. Push the plastic down onto the surface to prevent a skin forming on the curd.
Put it in the fridge and it will thicken as it cools.
How to make blueberry buttercream
To make blueberry buttercream you can use fresh or frozen blueberries. Pour the blueberries in a saucepan with 1 tablespoon of water and 1 teaspoon of sugar. Simmer over medium heat, breaking down the berries with a potato masher or a fork. When the blueberry liquid starts to thicken, it’s ready.
Use a spatula or spoon to push the berry mixture through a sieve. You only want the liquid puree, not the blueberry skins. Leave the blueberry puree to cool and make your buttercream.
This recipe uses my 4 Minute Buttercream and it's very simple to make. Mix together room temperature butter and powdered sugar or icing sugar until it’s smooth and then add vanilla.
Normally you’d add milk or cream to thin it out but not for this recipe. Instead, add the cooled blueberry puree a teaspoon at a time to flavour and colour the buttercream. Stop adding it when the consistency is easy to stir and your spatula leaves smooth trails in it. If you add too much liquid you’ll make the buttercream runny and it won’t hold its shape. Look at this gorgeous colour!
Put a large star tip like an 8B into a piping bag. Fill the bag about 3/4 full with the blueberry buttercream. I love the little flecks of berry in this! The reason for straining the puree to keep the skins out is that the skins will clog the piping tip.
To assemble your lemon and blueberry cake, pipe a dot of blueberry buttercream on the middle of a plate or cake board. Press your first lemon cake layer into that. This will hold it in place. Note: a turntable is useful but not essential for this recipe!
Pipe rosettes all around the outer edge of the cake, squeezing the piping bag to let the buttercream bulge out. Then pull up and away to make a peak on each rosette. Let the rosettes touch each other to form a wall around the edge of the cake and then spoon lemon curd into the middle.
For naked cakes like this with piped filling, I like to leave a slight dome on each layer. Also, I flip the layers over for the second and third layer. That way, the middle of each cake layer rests on the filling below it but the edges are slightly raised. This leaves more of the pretty colour and texture of the piped filling visible.
Make sure each layer is centered so it’s directly above the precious layer. This ensures a straight cake that doesn't lean.
Top the cake with blueberries, which give you that burst of juice when you bite into fresh fruit. The piping and blueberries also help you cut your cake into equal portions by including one or two or three rosettes and blueberries in each slice.
Store the leftovers of this lemon and blueberry cake in an airtight container like a Tupperware in the fridge for a week. I’m confident it will all be eaten before then! The cake tastes best at room temperature so take it out of the fridge about two hours before you serve it.
Here's the recipe for a three-layer 6" Lemon Blueberry Cake. The same quantities will make four 4" cakes (also three layers each) or of course you can divide the recipe by 4 to make just one 4" cake. For a three-layer 8" cake you can double the recipe.
An irresistible combination of zesty lemon cake, tangy lemon curd filling, sweet blueberry buttercream and juicy fresh blueberries! Double this recipe to make a three-layer 8" cake.
For the lemon cake layers:
1 1/2cups white sugar
2 teaspoons vanilla
2cups all-purpose (plain) flour
2 teaspoons baking powder
1/2cup sour cream
1/2cup whole milk (full fat)
For the lemon curd:
1 tablespoon lemon zest
1/3cup lemon juice (from about 4 lemons)
1/3cup granulated white sugar
1/4cup unsalted butter, cut into small pieces
For the blueberry buttercream:
1/2cup fresh or frozen blueberries
1 tablespoon water
1 teaspoon white sugar
1cup butter, room temperature
2 2/3cups powdered sugar
1/2 teaspoon vanilla extract
For the garnish:
9-16 fresh blueberries
To make the lemon cake layers:
In a mixer with a beater attachment, mix butter with sugar on medium speed until pale and creamy, about three minutes. Scrape down to the bottom of the bowl once during mixing to make sure no butter or sugar is stuck at the bottom.
Meanwhile, zest the lemons using a zester or the fine side of a grater. Add to the butter and sugar mixture and mix to combine. Add the eggs one at a time, mixing on the lowest speed after each egg until incorporated, about 30 seconds.
Add vanilla and mix on lowest speed for about 30 seconds to combine.
In a bowl sift and whisk together flour and baking powder. Add half of the mixture to the mixing bowl and mix on the lowest speed to incorporate.
Add milk and sour cream and mix into the batter. Add the rest of the flour mixture and mix only until just combined. The batter will be runny and pale in colour.
Grease three 6" pans and divide the batter between them. Tap the pans to flatten the batter or use a spatula to spread it flat.
Bake at 160ºC or 325ºF for 30 minutes or until a toothpick inserted into the middle of the cake comes out clean.
Let cakes cool in their pans for 5 minutes. Use a spatula to loosen cake from the edges of the cake pan and then turn onto a wire cooling rack. Leave to cool completely.
To make the lemon curd:
Put all of the lemon curd ingredients in a small saucepan over low or medium-low heat (depending on your stovetop). Bring to a simmer, whisking constantly until it thickens, which will take about 30 minutes. To test it, dip a spoon into it and it should coat the back of the spoon. Run your finger through that coating and you should leave a clear trail behind in the curd.
Pour the lemon curd through a sieve into a bowl, pushing through the sieve with a spoon if necessary.
Cover the bowl with plastic wrap, pushing it down to sit on the surface of the curd. Refrigerate for at least two hours and the curd will thicken more.
To make the blueberry buttercream:
Put the blueberries, water and white sugar in a small saucepan. Bring to a simmer over medium heat and mash the blueberries with a potato masher or fork. Simmer until the liquid thickens, about 5 minutes.
Pour the cooked blueberries into a sieve placed over a bowl and push the berries against the sieve using a spoon or spatula. Discard the blueberry skins and leave the blueberry puree in the bowl to cool.
Using an electric mixer, mix butter and powdered sugar on the lowest speed until smooth, about 4 minutes. Add vanilla and mix to combine.
Add the cooled blueberry puree a teaspoon at a time, mixing until the buttercream is easy to stir but still holds its shape.
Fit a piping bag with an open star piping tip like an 8B. Fill the bag no more than 3/4 full with blueberry buttercream.
To put it all together:
Pipe a dot of buttercream onto the middle of a plate or cake board and press your first layer of cake onto it. Pipe rosettes of the blueberry buttercream around the outer edge of the cake and spoon lemon curd into the middle.
Flip your next cake layer upside down and lower it onto the piping. Repeat the lemon and blueberry filling on this layer and then place the final layer on top, also upside down. Repeat the lemon and blueberry filling and gently press a fresh blueberry into the middle of each rosette.
If you don't have sour cream or milk you can omit both and substitute them with buttermilk.
You can refrigerate this cake for a week in an airtight container like a tupperware.
This cake is best served at room temperature! If you refrigerate it, take it out of the fridge two hours before serving it.
For a three-layer 8" cake, double this recipe (click "2X" at the top of the recipe).