This blackberry cake is bursting with berry flavor from the inside out. Soft, tender cake layers are filled with juicy blackberries, layered with a homemade blackberry compote, and finished with a naturally vibrant blackberry buttercream that's every bit as delicious as it looks. I've found using both buttermilk and sour cream creates an incredibly soft crumb, while frozen blackberries make this cake easy to enjoy any time of year. If you're looking for a showstopping layer cake that tastes just as beautiful as it looks, this is one I always look forward to baking.

up close of blackberry layer cake on a cake stand. — Three layers of blackberry goodness, naturally purple buttercream, and juicy berries in every bite... summer has never looked so delicious.

One of my favorite ways to enjoy berries is baking with them. If you've made my blackberry cheesecake before, you'll recognize that same sweet-tart blackberry flavor that makes it such a favorite. This cake takes those beautiful berries in a completely different direction with fluffy cake layers, homemade blackberry filling, and a naturally colored blackberry buttercream.

This blackberry cake is an excellent example of my love for baking with berries. For this cake recipe, you'll find blackberries in the cake batter, a blackberry compote filling, and a blackberry buttercream. And thanks to the stunning and vibrant colors of blackberries the frosting is naturally colored from the berries.

This post was sponsored by Oregon Berries. All opinions are my own. Thank you for supporting the brands that make Confessions of a Baking Queen possible.

Fresh Ingredients, Stunning Results

Frozen Blackberries: I love using frozen blackberries because they deliver great flavor year-round, and keeping them frozen helps prevent the cake batter from turning purple before baking.
Buttermilk + Sour Cream: I've found this combination creates an incredibly soft, tender cake that stays moist for days.
Lemon Zest: A little fresh lemon zest brightens the blackberry flavor without overpowering it.
Blackberry Compote: This homemade filling is what makes every slice taste packed with real blackberry flavor.
Blackberry Buttercream: My favorite part of this cake! The reserved blackberry filling naturally colors and flavors the buttercream without relying on food coloring.

For ingredient quantities please reference the recipe card below. On the recipe card there is a button for US or M (Metric) measurements.

Worth Every Beautiful Layer

dry ingredients for cake in a metal bowl with chunks of butter added. — Combine the cake flour, baking powder, baking soda, salt, lemon zest, and granulated sugar. Once fully combined for 30-60 seconds add the softened butter in chunks.

butter rubbed into dry ingredients. — Mix butteruntil incorporated and the mixture becomes like wet sand.

wet ingredients mixed together until combined. — Combine the buttermilk, sour cream, oil, and vanilla extract.

wet ingredients mixed into dry ingredients then eggs added. — Add the wet ingredients to dry ingredients and mix. Add in the eggs and mix to really combine.

blackberries tossed in flour and cake batter mixed together. — Use a rubber spatula to scrape the bottom of the bowl to make sure everything is evenly combined. In a small bowl combine the blackberries and flour.

blackberries mixed into yellow cake batter. — Gently mix in ¾ of the berries into the cake batter.

blackberry cakes before and after baking. — Pour cake batter into prepared pans and top with remaining blackberries scattered on top, then bake.

blackberry filling in a glass container. — Make blackberry filling.

blackberry compote added to buttercream to make blackberry frosting. — Make blackberry buttercream.

frosting dam piped on cake layer then blackberry filling added. — Frost cake layers and fill with blackberry compote.

cake added and frosted in pink frosting. — Place the second cake layer on top, add a thin layer of frosting around the whole cake to create a crumb coat.

blackberry frosting spread onto layer cake. — Frost the cake with remaining frosting and use a angled spatula to create a design.

blackberry layer cake with blackberries and tea,

There you go, this beautiful blackberry layer cake is perfect for an afternoon tea party, a Sunday night dinner, or birthday celebration!

I hope you love this soft, tender cake as much as we do!

slice of cake on a plate with lots of blackberries.

Storage Advice

Store the cake in an airtight container in the refrigerator. If you don't have a large enough container, you can use place some toothpicks on the cake poking up and place plastic wrap all over- the toothpicks will hold the plastic wrap up preventing it from ruining the icing.

Ideally, though, let the cake sit out at room temperature for a bit before serving.

Liz's Tips for Recipe Success

Use room temperature ingredients.
Weigh your ingredients, I suggest a digital scale.
Let the cakes fully cool otherwise you risk the frosting melting off of the cake.
For the best tasting cake, let a slice sit at room temperature for 15-20 minutes to take the chill off.

up close of a bite of cake on a plate next to berries.

★★★★★ Please let me know if you make this recipe by leaving a star rating and comment below!

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Recipe Card

Soft Blackberry Cake with Creamy Blackberry Buttercream

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Print Recipe

Total Time: 3 Hours
Yield: 10-12 Slices 1x

Instructions

Cake

Preheat the oven to 350F/180C and heavily grease two 9-inch cake pans, and set them aside. Your oven must be properly preheated for your cake to bake properly.
In a bowl of an electric stand mixer fitted with a paddle attachment or a large bowl with an electric handheld mixer combine the cake flour, baking powder, baking soda, salt, lemon zest, and granulated sugar. Once fully combined for 30-60 seconds add the softened butter in chunks and mix until incorporated and the mixture becomes like wet sand.
In a bowl combine the buttermilk, sour cream, oil, and vanilla extract then add to dry ingredients and mix for 60 seconds, you want to really incorporate everything to make sure the batter builds structure. Add in the eggs and mix for an additional 45-60 seconds, there should be no trace of egg left. Use a rubber spatula to scrape the bottom of the bowl to make sure everything is evenly combined. In a small bowl combine the blackberries and flour. Gently mix in ¾ of the berries into the cake batter. Pour cake batter into prepared pans and top with remaining blackberries scattered on top, gently press into cake batter ever so slightly.
Quickly and gently place the pans in the oven and do not open the oven door until at least the 20-minute mark, if you have an oven light use it! Do this very quickly and don't close the door too abruptly. Your cakes should be done baking in 25-30 minutes. If you press a toothpick into the center it should come out with no wet batter, or you can gently press the top center of the cake and it should bounce back immediately, the sides of the cake will be coming away from the edges of the pan. Set on a wire rack to cool for 30 minutes before inverting onto the wire rack to cool completely before decorating.

Blackbery Filling

While the cake is baking. In a small bowl whisk together the cornstarch and lemon juice to create a slurry.
In a large pot add all ingredients and cook over low-medium heat for 4-5 minutes, stirring frequently. You want to bring the mixture to a slight boil then, reduce the heat and continue to stir. The berries will naturally sort of break down. The longer you cook it the more reduced it will become. Pour into a heat proof container.
Let cool for 30 minutes then store in the fridge to chill.

Frosting

Once the cakes have cooled and the blackberry filling has chilled. In the bowl of an electric mixer fitted with a paddle attachment, or a large bowl with a handheld mixer beat the butter for 5 full minutes, until light and fluffy.
Sieve the powdered sugar to prevent any lumps and add half to butter. Beat for another 5 minutes then add the remaining powdered sugar and mix for 3 more minutes. Make sure to scrape down the sides of the bowl multiple times to ensure everything is evenly combined.
Add the vanilla extract and heavy cream and beat for another 2 minutes. Mix in the 4 tablespoons of blackberry filling and scrape the bowl to ensure no white spots remain.
Using a serrated knife saw off the dome of the cake to create a flatter, even surface. Place the bottom layer on the serving plate and place a large dollop of frosting on the cake then use a small angled spatula to spread an even layer of frosting onto the first cake layer. Then pipe a border of frosting to create a dam for the filling. Spread the ¾ of the blackberry filling into the cake center and spread into an even layer, making sure not to go over the frosting dam. Make sure to get down and look at the cake at eye level to see if it is level or not, and adjust as necessary. Place the second cake layer on top, add a thin layer of frosting around the whole cake to create a crumb coat, then place the cake in the fridge for 30 minutes or freezer for 10 minutes to set it. Frost with remaining frosting and add blackberries to the cake.
Store the cake in an air-tight container in the refrigerator for up to 5 days, although best tasting the first two days. For best results, let the cake come to room temperature for 10-15 minutes before enjoying a slice.