This blackberry lemon poppyseed cake has a lemon poppyseed cake with a lemon soak, fresh blackberry buttercream, and a lemon cream cheese frosting. This cake is my dream cake!
I don’t usually make my own birthday cake, but I’d been dreaming about a blackberry lemon poppyseed cake like this for months so my birthday seemed like the perfect excuse (not that you ever really need an excuse) to make this cake! I knew exactly what I wanted right down to how I wanted to decorate it.
I knew I wanted to it to be super romantic looking, like it came out of a fairy garden. I knew I wanted flowers, pastel colors, and white chocolate butterflies flitting around. Don’t worry, I’ve got a tutorial on how I made those cute butterflies.
Tips for making this cake a success!
The cake recipe is adapted from Technicolor Kitchen. There are a couple things in this recipe that are super important.
Buttermilk has a different structure from regular milk. It is thicker and tangier than milk and it unique structure makes the cake super tender. Buttermilk is also acidic, where milk ranks a lot lower on the acidic scale. The lactic acid reacts with the baking soda and helps make the cake rise.
I really do recommend you get the real deal, but if it’s not available in your area here’s what you can substitute instead.
This recipe calls for 1 ¼ cups of buttermilk, so instead you could do:
- 1 ¼ cups milk + 4 teaspoons lemon juice—then let stand for 10 minutes
- One scant cup plain yogurt + ¼ cup water, mixed together
- If using thick Greek yogurt, do 1 heaping cup plain Greek yogurt + ¼ cup water mixed together
Room temperature butter
Some times people get carried way softening their butter. It is very important that the butter is soft NOT melted. When butter is soft you can whip air into it, which is important to the cake’s structure.
Soaking your Poppyseeds
It’s very important that you soak your poppyseeds in water for an hour before adding them to your cake batter. And make sure you drain the water off of your poppyseeds super well before adding them in to your batter, you don’t want to add in extra liquid or it will change the texture of your cake. I used a paper towel to strain the water.
Ooh how I love this lemon syrup. This is where a lot of the lemon flavor comes in. Without this the cake is very lightly lemon flavored, this lemon syrup not only adds moisture to the cake but also gives you the punch of lemon flavor. So don’t be shy, be generous with that syrup. I use allllll of it and don’t regret it for a second.
Tips for Frosting and Decorating Your Blackberry Lemon Poppyseed Cake
Start with a crumb coat & then freeze
Spread of thin layer of frosting all around your assembled cake and then freeze it for 15 minutes. This ensures that you don’t get any extra little cake crumbs in your cake when you’re frosting it.
Use a Cake Scraper
Then apply your frosting. I like to use a cake scraper—holding it straight up and down against the cake, scrape the frosting so that it’s smooth and even around the cake.
Freeze Your Decorations
For the decoration of this cake I piped flowers, rosettes, little stars, and used fresh mint leaves, fresh blackberries, and white chocolate butterflies that I piped. With the flowers and rosettes I piped them on parchment paper and froze them before placing them on the cake. This made it super easy to arrange the flowers on the top of the cake.
I’ve got a tutorial here that shows you how to make these white chocolate butterflies!
Enjoy and Happy Baking!
If you LOVE cake as much as we do, check out these other fabulous cake ideas:
- Hidden Heart Bundt Cake
- Raspberry Mousse Chocolate Cake
- Raspberry Cream Crepe Cake
- Easy Vanilla Layer Cake
- Perfect Chocolate Cake
- Southern Chocolate Coca-Cola Cake
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Blackberry Lemon Poppyseed Cake
Lemon Poppy Seed Cake:
- 3 cups cake flour measured correctly
- 1 ¾ cup granulated sugar
- 2 teaspoons baking powder
- 2 teaspoons baking soda
- ½ teaspoon salt
- 3 tablespoons poppy seeds soaked in water first (see notes)
- 1 cup of butter room temperature
- Zest of 3 large lemons about 3-4 tablespoons of zest
- 1 teaspoon pure lemon extract
- 1 ¼ cups buttermilk
- 5 egg large whites
- Juice of 2 large lemons (about ½ cup of lemon juice
- ¼ cup sugar
Lemon Cream Cheese Frosting:
- 5 ounces 10 tablespoons cream cheese, room temperature
- 1 ½ cups butter room temperature
- 7 cups powdered sugar
- ⅛ teaspoon salt
- ½ teaspoon vanilla
- 1 teaspoon lemon extract
- 1 tablespoon lemon zest the zest of 1 lemon
Blackberry Buttercream Frosting:
- 1 cup blackberries
- 2 tablespoons lemon juice
- 1 cup butter room temperature
- 4 cups powdered sugar
- 1 tablespoon lemon zest the zest of 1 lemon
- ⅛ teaspoon salt
- Preheat oven to 350 degrees Fahrenheit. Line either 3 8-inch pans OR 4 6-inch pans with parchment paper AND grease.
- In a large bowl or stand mixer combine flour, sugar, baking powder, baking soda, salt, and poppy seeds mix together so that there are no lumps.
- Add in lemon zest and lemon extract. Alternate adding in a few tablespoons of butter and buttermilk (reserve ¼ cup of buttermilk). Beat on low for 1 minute, then beat on medium for 2 minutes. This will whip air into the batter. Don’t forget to scrape the sides down!
- In a bowl combine egg whites and the reserved ¼ cup of buttermilk. Whisk together. Then add into your batter. Beat on low until it is fully combined. You don’t want to over beat your mixture or you’ll make your cake tough.
- Divide the batter evenly between your lined and greased cake pans. If you are using the 8 inch pans bake for 22-28 minutes OR if you are using the 6 inch pans bake for 22-25 minutes. Start checking your cakes around 20 minutes. Insert a toothpick in the center, you should have a few moist crumbs but no batter on it.
- Let your cakes cool in their pans for 10 minutes and then remove from their pans and let cool on cake racks. While cakes are cooling prepare your lemon syrup.
- While cakes are cooling prepare your lemon syrup. In a small saucepan over medium heat add lemon juice and sugar. Bring to a boil and let boil for 1 minute until the sugar is completely dissolved.
- If your cakes are domed in the middle level them off so they are flat. Use a toothpick to poke small holes all over the top of the cake and generously brush the lemon syrup over the tops of the cake, trust me you'll want to use all the syrup. Let cool completely.
Lemon Cream Cheese Frosting;
- Beat butter and cream cheese together until fluffy. Add in 1 cup of powdered sugar, vanilla, lemon extract, and salt and cream together.
- Add in the remaining powdered sugar, 1 cup at a time, until smooth and fluffy.
- In a small sauce pan over medium heat add your blackberries and lemon juice. Stir constantly until blackberries begin to soften. Mash them as you stir with your spoon. Cook for 5-7 minutes until you have a thick jammy mixture.
- Place your blackberry mixture and softened butter into a food processor or a high speed blender and blend together until smooth. This will get rid of most of the seeds. Cool butter and jam mixture.
- If you don’t have a high-speed blender or food processor you can push the jam through a mesh strainer and then cool it before creaming the jam and butter together.
- Once cool beat your blackberry butter until light and fluffy. Add in 1 cup of powdered sugar, salt, and lemon zest and beat. Slowly add in the remaining powdered sugar and cream together until smooth and fluffy.
- Place 1 cake layer bottom side down on your cake plate. Spread a very thin layer of lemon cream cheese frosting over the top of the cake. Then spread about ½-¾ cup of blackberry buttercream over top. Make sure the frosting is super level. Repeat for the next 2 layers.
- Place your final cake layer bottom side up so you have a nice flat cake for your top layer.
- Cover the top and outside of the cake with a thin layer of the lemon cream cheese frosting to act as a crumb coat. Place entire cake in the freezer for 15 minutes or in the fridge for 30 minutes. Once chilled completely frost the cake.
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