Moist and velvety lemon cake with juicy raspberry filling and raspberry buttercream frosting. Based on our lemon velvet cake, this recipe highlights the sweet flavor of fresh raspberries and the subtle tang of lemons.
Add your raspberries and sugar to a medium-sized saucepan over medium heat.
Heat your raspberry puree until it begins to bubble. Increase the heat to medium-high heat if needed.
In a small bowl, combine the water and the ClearJel (or cornstarch) and mix until smooth. Don't just add the ClearJel (or cornstarch) directly to the hot liquid or you'll end up with lumps of thickener in your filling.
Add your ClearJel mixture (or cornstarch slurry) to the hot liquid and mix for one more minute to thicken the mixture.
Add in the lemon juice and lemon zest and continue cooking for one more minute until thickened.
Transfer the mixture to a heat-proof container and cover it with plastic wrap (so that it's touching the surface) and allow it to cool to room temperature or place it into the refrigerator to cool before using it.
Making Lemon Raspberry Cake
Preheat the oven to 335º F/168º C or 350º F/177º C and prepare three 6-inch cake pans (or two 8-inch pans) with cake goop or another preferred pan spray or parchment paper. Make sure all ingredients are at room temperature or slightly warm (eggs, buttermilk, butter).
Measure out the buttermilk and place 4 ounces in a separate measuring cup.
Add oil to the 4 ounces of buttermilk and set aside.
To the remaining buttermilk, add your eggs (lightly whisked to break them up), lemon extract, lemon juice, and lemon zest.
Measure out the cake flour, sugar, salt, baking powder, and baking soda into the bowl of your stand mixer.
Attach the paddle to the mixer and mix on low speed (setting 1 on Kitchen Aid mixers) until the dry ingredients are combined. I recommend a stand mixer for this recipe, but you can do this with a large bowl and electric mixer, just mix by texture instead of time.
Slowly add chunks of softened butter to the flour mixture and mix on medium speed until the batter resembles coarse sand.
Add the milk/oil mixture all at once to the dry ingredients and mix on medium speed (speed 4 on Kitchenaid) for 2 full minutes until it's white and fluffy.
Scrape the bowl. This is an important step because if you skip it, you will have hard lumps of flour in your batter. If you do it later, they will not mix in fully.
Slowly add in the rest of your wet ingredients in 3 parts and mix until combined. Stop to scrape the sides of the bowl one more time halfway through. Your batter should be thick and not too runny.
Fill the pans ¾ full and give each a tap to level out the batter and get rid of any air bubbles.
Add 3 to 4 large dollops of your raspberry filling to the cake batter and use a spoon or knife to swirl it through the batter.
Bake the cakes for 35 to 40 minutes until a toothpick inserted in the center comes out with a few crumbs.
After the cakes have cooled for 10 minutes, flip them onto cooling racks to cool completely. Or wrap them in plastic wrap and freeze them.
How to Make Raspberry Buttercream
Place the egg whites and powdered sugar in the bowl of your stand mixer with the whisk attachment and whip on high speed for 3-5 minutes.
Add the softened butter in small chunks then vanilla and salt. Whip on high until light and fluffy and white, about 8 to 10 minutes.
Set aside 2 cups of vanilla buttercream if you want to do the ombre design. Add a drop of yellow food color to give it a slight tint.
Add about ½ cup of the strained raspberry purée to the buttercream and continue to whip until combined.
Mix in about 1-2 drops of pink food coloring to enhance the raspberry color if you choose.
Optional: switch to the paddle attachment and mix on low for 15-20 minutes until all air bubbles are gone.
Stored it in an airtight container for up to a week in the refrigerator or for 3 months in the freezer.
Assembling and Decorating the Cake
Trim the dome from the top of the cake rounds and the browned edges.
Place the first cake layer on the cake board and spread raspberry buttercream over the top. Using a piping bag and round tip, pipe a dam around the outer edge of the cake.
Spread 1 to 2 tablespoons of raspberry filling within the dammed area. If you overfill the center it could possibly squeeze out once you start stacking other layers.
Place a few fresh raspberries on top of the raspberry filling.
Spread a thin layer of raspberry frosting on the bottom of the next layer to sandwich in the berries.
Repeat the process with the remaining cake layers.
Once all 3 layers are placed, cover it in a crumb coat of buttercream. Chill it for 5-10 minutes until the buttercream has set.
Spread a final coat of buttercream on the cake. I used the yellow buttercream to make an ombré, but you can do all raspberry if you prefer.
Spread some raspberry buttercream around the bottom half of the cake.
Then smooth the whole cake using the bench scraper, creating an ombré, watercolor effect between the 2 buttercream colors.
Using a piping bag fitted with a star tip, pipe 8-10 dollops on top around the cake. (Make sure the dollops and raspberries are touching, to create a dam for the center raspberry filling.)
Then, fill the center of the top of the cake with 2-3 tablespoons of raspberry filling.
Make sure to keep the cake chilled, but take it out a few hours before you're going to serve it. This cake is best eaten at room temperature!
Notes
Weigh your ingredients to avoid cake failure. Using a kitchen scale for baking is super easy and gives you the best results every single time.
Make sure all your cold ingredients are room temperature or slightly warm (butter, milk, eggs, to create a cohesive batter. Curdled batter causes cakes to collapse.
To prevent blueberries from sinking, I wash them (to get them wet) then roll them in flour. Then I add them to the batter halfway through baking
Do not fall for the “just add cornstarch to regular flour” trick. It does not work for this recipe. Your cake will look and taste like cornbread. If you can’t find cake flour, use pastry flour which isn’t quite as soft as cake flour but it’s better than all-purpose flour.
Make your own pan release (cake goop!) The best pan release ever!
If you’re in the UK search for Shipton mills cake and pastry flour. If you’re in another part of the country, search for low protein cake flour.
Make the raspberry filling first, then make the lemon cake and swirl in the filling, bake it, and then make the buttercream while the cakes are cooling.