Standing 6-layers tall, this Blackberry Lavender Cake is the perfect balance between sweet, tart, and floral flavors. Infusing aromatic, crushed lavender into the batter elevates this basic butter cake without making it taste too perfume-y or soapy. Painted with lilac and lavender shades of silky Swiss meringue buttercream, this cake is perfect for any spring or summer celebration.
Don’t be intimidated by the height of this cake. Instead, think of the 6 layers as just three cakes, split into two layers each. That is, in fact, all that is being done here.
When working with something as sweet and thin as a jam filling, it is difficult to build layer cakes the same as their buttercream-filled counterparts. J
am and buttercream fillings vary so much, so it only makes sense to give them different treatments.
For buttercream, fudge, and cream cheese, the filling is half the height of the cake layers. So, if my cakes layers are 1-inch tall each, I add about ½-inch of filling between each layer.
A ½-inch layer of something like jam or rich chocolate ganache can be overpowering. Instead, thinner layers (and more of them) help balance out the overall texture and flavor of the cake.
Especially in a cake where the baked layers are rather thick, like in this recipe, splitting the layers in half and dispersing the jam between them makes for a better cake.
How to Stack and Fill a Layer Cake
Worried that a cake this tall might tower over? A buttercream “dam” helps hold in the loose filling and keeps it from slipping out between the layers.
The dam also helps secure the layers together as you build the cakes.
A crumb coat not only locks in crumbs, but it glues the cake together the keep the layers from slipping and sliding as you go to ice the cake.
To create a buttercream dam, fill a piping bag with a medium round tip, or a cut bag with an opening of about a ½-inch, with the same buttercream or frosting that will be used on the outside of the cake.
When you go to build your cake, pipe a ring around the top edge of each layer of cake.
Fill this ring with looser fillings like jam, pastry cream, or ganache. Place the next layer of cake on top and repeat.
To crumb coat the cake, spread a thin layer of buttercream all over the stacked and filled cake. This layer of icing doesn’t have to be perfect.
The idea is to lock in any loose crumbs and prevent them from mixing into the final coat of frosting. Chill the crumb-coated cake for about 15 minutes before adding the outer layer of frosting.
Adding Floral Flavors to Cakes
This recipe comes from the new book, Blooms and Baking, by Amy Ho. Amy is a local friend on my mine and the editor behind the Saveur-nominated baking blog, Constellation Inspiration. Her romantic bakes and flower-covered cakes that grace her website can now be found in her beautifully photographed book.
- Use a buttercream “dam” to prevent the jam from slipping out from between the layers of cake. The buttercream will also help secure the layers together as you stack the cake.
- Mix the finished buttercream on low speed to remove larger air bubbles. It should be silky smooth with a texture similar to mayonnaise.
- If you don’t have ground lavender or a spice grinder, use a mortar and pestle to grind the lavender with some of the sugar called for in the cake recipe. Use a mesh sieve to sift out any larger pieces of lavender left behind.
- I used store-bought, seedless jam for the filling. Homemade jam would be a welcomed addition, especially during berry season!
- When splitting the cakes in half to form the layers, use a long serrated knife. Gently score around the middle of the cake then carefully make little cuts towards the center of the cake until it splits into two layer.
For the frosting, use a ½ batch of this Swiss Meringue Buttercream.
Blackberry Lavender Cake
- 3 cups all-purpose flour
- 3 tablespoon cornstarch
- 1 tablespoon baking powder
- ½ teaspoon baking soda
- ½ teaspoon salt
- 1 cup whole milk
- ⅔ cup sour cream
- 1 teaspoon pure vanilla extract
- 1 ¾ cups granulated sugar
- ½ teaspoon dried culinary lavender
- 1 cup unsalted butter softened
- 3 large eggs
- 2 large egg yolks
- 1 ¼ cups blackberry jam
- ½ batch Swiss Meringue Buttercream
- Preheat the oven to 350°F. Grease three 6-inch cake pans and line the bottoms with parchment paper. Set aside.
- Whisk together the flour, cornstarch, baking powder, baking soda, and salt. Set aside. In a separate bowl, whisk together the milk, sour cream, and vanilla. Set aside.
- Grind down the lavender in a spice grinder. Alternatively, use a mortar and pestle to grind down the lavender with a tablespoon of sugar. Use a mesh sieve to sift out any large pieces of lavender.
- Place the lavender, sugar, and butter in the bowl of a stand mixer fitted with a paddle attachment. Cream together the butter, lavender, and sugar until light and fluffy (about 3 minutes on medium speed). Stop the mixer and scrape down the sides of the bowl. With the mixer on low, add the eggs and egg yolks - one at a time, allowing for each egg to be absorbed before adding the next. Stop the mixer and scrape down the bowl.
- Add about half of the flour mixture and mix on low until combined. Stream in the milk mixture and mix until smooth. Add the remaining flour mixture and mix until the batter is combined.
- Evenly distribute the batter between the prepared pans. Bake the cakes for 34 to 36 minutes, or until a toothpick inserted into the center of the cakes comes out clean. Cool the cakes on a wire rack for 15 minutes before removing the cakes from their pans. Continue to cool completely before filling and frosting the cakes.
- Once the cakes have completely cooled, slice them each in half horizontally. You will have 6 layers of cake. Place one layer of cake on a cake board or serving dish. Fill a piping bag fitted with a medium round tip (or use a plastic zip-top bag and snip the tip) with buttercream. Pipe a ring around the top edge of the cake. The ring should be ¼ to ½-inch tall. The buttercream will act as a dam to keep the jam in and help adhere the layers together so they don’t slip and slide around.
- Spoon about ¼ up of blackberry jam into the center of the cake. Spread with an offset spatula or the back of the spoon. The dam won’t be filled with jam - that is okay. Top the blackberry jam with the next layer of cake and gently press down to secure. Some of the buttercream way squish out of the sides. As long as not too much jam has slipped out, it is okay!
- Repeat with the remaining cake layers and jam. Spread around any of the buttercream that may have slipped out the sides onto the cake. Add more buttercream to the top of the cake and spread all around to create a thin crumb coat. Chill the cake for about 15 minutes.
- To decorate, divide the remaining buttercream into three bowls. Tint the buttercream with gel food coloring. Start icing the sides of the cake. Working with one color at a time, swipe on the buttercream in a zigzag motion with the tip of an offset spatula. It is easiest to work in patches. Continue adding patches of buttercream, alternating the colors and direction of your spatula strokes. Mixing up some of the colors as you go in encouraged. Continue until the sides are completely covered.
- Once the sides are complete, clean up the top edge of the cake. Take the edge of an offset spatulas and gently pull any excess frosting towards the center of the top of the cake. Repeat the zigzag motion on the top of the cake.