You know it’s going to be a good day when you get to make a spectacular birthday cake for your mom. I texted her the other day to find out what she wanted for her special day. She sent me pictures of cakes with berries, so I decided to make her this marionberry lavender layer cake. Last summer I made a bunch of jars of marionberry lavender jam and gave her one. She sent me a picture a couple weeks later with an empty jar. So I thought what a perfect choice to have that be her special cake.
The cake is a simple vanilla, but the buttercream and marionberry filling really put this cake over the top in the flavor department. I realized after we cut into the cake, that I could have added a lot more of the jam filling. It’s hard to know how much is too much. When a cake is three layers, it’s important that it stay together and not topple over from too much filling!
Tips for getting a perfectly even cake
Last year I bought some cake strips from King Arthur Flour. I had heard of them before, but never thought to try them. They come in a set of two. Prior to filling your pans with batter, soak the strips in water for 15 minutes. Wring out the excess water, wrap around the pan and adhere with the velcro. Fill the pan with batter and bang it on the counter a couple times. This helps release any air bubbles and the cake strips prevent the cake from doming in the middle.
If you end up with a domed cake, it’s easy to fix. Remove the cake from the pan, place it on a stable, flat surface, and run a serrated knife over the top to even it out. You can also flip the cakes upside down to get a flat surface. Just make sure you add enough filling to even it out.
The buttercream is kind of time consuming, but worth it to me. I had never made german buttercream before. SeriousEats.com has an amazing recipe and I added some strained marionberry jam to give it that cool ombre color. I love to experiment with different recipes and thought it would be fun to see how this turned out. Kinda risky. But it worked!
This recipe calls for a lot of butter. Five sticks to be exact. Kind of a scary thought – 2 1/2 cups of buttah. But because I don’t eat cake like this every day, it’s okay to splurge every once in a while for a special occasion.
Tips for making buttercream
First, when beating the butter in your stand mixer, it is very important to have the butter at room temperature. I usually take the butter out the night before, just so it can come to room temperature slowly and be ready for baking first thing in the morning. I try not to soften it in the microwave just because if it melts, it will ruin what you’re trying to accomplish.
Second, if the buttercream is not a creamy consistency, there are ways to fix this. SeriousEats has an amazing article to help fix any buttercream emergencies. The link is for swiss buttercream, but it works for this german buttercream as well. When I made this recipe, it actually “curdled”. I followed the directions to fix it and it worked! I was so impressed. So if you “mess up”, don’t panic! It’s totally fixable.
Lastly, if you don’t plan on using the buttercream right away, it’s important to refrigerate it. It will need to soften a bit before piping or spreading it on your cake. But if left out, the consistency will change and you might need to cool it down again and re-whip it. It’s an amazing frosting, but needs some TLC to do its job.
Hope you enjoy this marionberry lavender layer cake as much as my mom did!
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For the cake:
- 1 cup neutral oil (canola, vegetable)
- 1/2 cup greek yogurt
- 3 eggs, room temperature
- 2 cups sugar
- 1 tablespoon vanilla extract
- 1 1/2 cups buttermilk, shaken
- 3 3/4 cups all purpose flour
- 1 1/2 teaspoons baking soda
- 1 teaspoon baking powder
- 1 teaspoon salt
For the marionberry filling:
- 3 cups frozen marionberries
- 1/4 cup honey
- juice from one lemon
- 1 teaspoon culinary lavender
- 2 teaspoons King Arthur clearjel
For the buttercream:
- 1 1/2 cups whole milk
- 1 tablespoon vanilla
- 1 cup plus 2 tablespoons sugar
- 3 tablespoons cornstarch
- 1 egg
- 2 egg yolks
- 5 sticks unsalted butter, room temperature
To make the cakes:
- Preheat oven to 350 degrees. Lightly spray non-stick on three 8″ cake pans. Line with parchment and lightly spray.
- In the bowl of a stand mixer fitted with the paddle, beat the oil, greek yogurt, egg, yolks, sugar, vanilla, and buttermilk.
- In a medium bowl whisk together the flour, baking soda, baking powder, and salt. Add dry ingredients to wet ingredients and mix until just combined.
- Divide batter, a generous 1 1/2 cups, among cake pans. Bang on the counter to remove any air bubbles.
- Bake 30-35 minutes, until tops are lightly golden and the centers don’t wobble when shaking the pan. Cool on rack for 5 minutes, then remove cakes from pan and continue cooling. Wrap in plastic wrap and refrigerate until ready to assemble the cake.
To make the marionberry filling:
- In a medium saucepan, combine the berries, honey, lemon juice, lavender and clearjel.
- Cook on medium heat until mixture bubbles and thickens. Using an immersion blender, break up berries to desired consistency. Continue cooking for 5-7 minutes. Cool mixture and then place in fridge to thicken up.
To make buttercream:
- In a small saucepan over medium low heat, combine milk and vanilla. Bring to a scald and turn on low heat.
- In a medium bowl, whisk together sugar and cornstarch. Add egg and yolks and whisk together.
- Slowly add in 1/2 cup of the warmed milk and whisk constantly. Repeat with two more 1/2 cup additions until milk mixture is completely incorporated into egg mixture.
- Return mixture to saucepan and cook over medium heat, whisking constantly. Once mixture thickens (about 3 minutes), continue cooking and whisking for another 2 minutes (set a timer).
- Pour custard into large, shallow dish to cool. Place a piece of plastic wrap over the surface of the mixture to prevent a skin from forming. Refrigerate at least 1 hour, roughly to 68 degrees.
- In the bowl of a stand mixer fitted with a paddle attachment, beat the softened butter on medium speed until light and fluffy, approximately 5 minutes.
- Use a rubber spatula to stir the custard mixture. Add a couple tablespoons at a time to the mixing bowl, stopping and scraping down the bowl every few additions.
- Switch to the whisk attachment and whip mixture on medium speed until buttercream is airy, soft and light in color.
To assemble cake:
- Place one cake layer on cake stand and spread a thin layer of buttercream on the top. Fill a pastry bag with buttercream and a piping tip and pipe a rim around the edge of the cake.
- Fill the center with the marionberry lavender jam and add the second layer of cake.
- Repeat process with second layer.
- Flip the third layer of cake upside down – this ensures a flat surface – and place on top. Frost with a decorating tip, or use an offset spatula to spread the buttercream.
- Refrigerate until ready to serve.
Keywords: marionberry, lavender, layer cake, buttercream