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Keeping this sweet, simple, and delicious with this Swirled Blackberry Lavender Sheet Cake. Light and fluffy vanilla cake swirled with homemade blackberry lavender jam. Then generously frosted a sweet vanilla bean white chocolate buttercream. This cake is nothing short of delicious. Every bite is layered with fresh berries, hints of lavender, and sweet vanilla cake. The perfect berry-filled cake for any and all occasions.
Happiest Friday everyone. We’re celebrating sweet cake and I am so excited. I’ve been holding onto this for a couple of weeks. I’ve wanted to share this since the day I first made it, but peach recipes took top priority last week. Which is totally fine, because of course, they too are so delicious.
This week, however, we’re switching to berries, cake, and frosting and it’s going to be pretty darn great.
The Inspiration
I would love to say that the inspiration for this cake was Asher’s upcoming 13th birthday. BUT, that girl wants nothing to do with a non-chocolate cake. So, as much as I would love to be remaking this for her birthday on the 30th, I’m sure I’ll be making the standard chocolate cake.
The real inspiration was super simple, I wanted to bake a cake. I wanted it to be light and happy and pretty. I want to have fun photographing it, and I wanted it to be my most delicious vanilla cake yet.
Excitedly reporting that this cake checks all of the above boxes. Sometimes you just have to make what you really, really want to make.
The details – starting with the jam
If you guys have followed along for a while you may remember my blackberry layer cake. This cake is very, very similar flavor-wise, but it’s simplified down into a yummy sheet cake.
The jam is quick, but delicious…fresh blackberries, sweet honey, dried lavender, and a squeeze of lemon. Boil everything together until the jam thickens up and turns jammy.
This isn’t your traditional jam however, it will not be jelly-like. It’s more of a sweet, thick blackberry sauce. Make the jam first so that it has plenty of time to cool off.
Pairing lavender with blackberries is a favorite combo of mine. The flora hints from the lavender compliment the sweetness of the blackberries, and when mixed together in a jam…
It is so good!
Onto the vanilla cake
When it comes to vanilla cake I like to keep my cake recipes pretty straightforward. And I always go heavy on the vanilla. I love to use real vanilla beans for added flavor, but of course, good olè vanilla extract works great too.
Mix the coconut oil with sour cream, eggs, sugar, and that vanilla. Then just add flour, baking powder, baking soda, and a nice pinch of salt. Stream in a little milk and that’s it. Simple. Simple.
Now pour the batter into a rectangle baker.
Now the fun part – swirl in the jam
Take the blackberry jam from earlier and dollop spoonfuls over the cake batter, then use a knife to gently swirl the jam around. Don’t over mix, the idea is to have pretty swirls of jam throughout the cake.
If you over-swirl, the cake will still be great, but more of a purple color.
While the cake bakes, make the frosting
Butter, sugar, lots of vanilla, and melted white chocolate, that’s what you’ll need. Beat that all together and you’ll have one of my favorite cake frostings.
No one ever knows there’s white chocolate in the frosting. But it’s what makes this buttercream extra special and leaves everyone wanting more.
Finish this up
Once the cake has cooled, spread over a thin layer of the blackberry jam, then dollop over that frosting. The frosting is sweet and creamy, and everything together is DELICIOUS.
Once again, take the jam and add small spoonfuls to the top of the baked cake. Then use a knife to gently swirl the jam into the frosting. It turns the prettiest shade of purple and I love it.
Yes, what I love most about this sheet cake is how just pretty it turns out with minimal effort. The beauty of a sheet cake is that you don’t have to cut or layer anything. Just bake, frost, and enjoy!
This is the perfect cake to make on a rainy summer afternoon. Especially if you have one too many boxes of sweet berries!
Looking for other sweet cake recipes? Here are some favorites:
Swirled Berry Ice Cream Butter Cake
Swirled Blueberry Lemon Thyme Cake
Coffee and Fudge Ice Cream Cak
Lastly, if you make this Swirled Blackberry Lavender Sheet Cake, be sure to leave a comment and/or give this recipe a rating! Above all, I love to hear from you guys and always do my best to respond to each and every comment. And of course, if you do make this recipe, don’t forget to tag me on Instagram! Looking through the photos of recipes you all have made is my favorite!
Swirled Blackberry Lavender Sheet Cake
Servings: 12
Calories Per Serving: 781 kcal
Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
Watch the How-To Reel
Ingredients
Blackberry Lavender Jam
- 6 cups fresh or frozen blackberries
- 1/2 cup honey
- 1 tablespoon lemon juice
- 1-2 tablespoons dried lavender
Blackberry Cake
- 1 cup melted coconut oil
- 1/2 cup sour cream
- 3 large eggs
- 1 1/2 cups granulated sugar
- 1 tablespoon vanilla extract
- 1 cup milk
- 3 cups all purpose flour
- 1/2 teaspoon baking soda
- 1 1/2 teaspoons baking powder
- 1 teaspoon kosher salt
Vanilla White Chocolate Frosting
- 2 sticks (16 tablespoons) salted butter, at room temperature
- 1 1/2 cups powdered sugar
- 6 ounces white chocolate, melted and cooled
- 1 teaspoon vanilla extract
Instructions
- 1. To make the jam. Add the blackberries, honey, lemon juice, and lavender to a medium-size pot set over high heat. Bring the mixture to a boil, once boiling use a potato masher or fork to break down and mash the berries. Continue to cook for 5-8 minutes or until the jam has reduced and thickened by 1/3. Remove from the heat and let cool. This should thicken as it cools. 2. Preheat oven to 350° F. Line a 9×13 inch baking dish with parchment paper.3. In a large bowl, beat together the coconut oil, sour cream, eggs, sugar, and vanilla. Add the flour, baking soda, baking powder, and salt. Mix until just combined, then slowly beat in the milk until fully combined 4. Pour the batter into the prepared pan. Take about 1/2 cup to 3/4 cup of the jam and dollop it by the tablespoon over the cake. Use a knife to lightly swirl the jam around, don't over mix it. 5. Bake 30-35 minutes, until the top is just set and no longer wiggly in the center. Remove and let cool completely before frosting. 6. To make the frosting. In a large bowl, beat together the butter and powdered sugar until light and fluffy. Add the melted white chocolate and vanilla, beat until combined.7. Spread a thin layer of jam over the cake, then frost the cake all over. Add small spoonfuls of the jam to the frosting and gently swirl the jam into the frosting. Slice, eat and enjoy!
This post was originally published on August 20, 2021
Can I substitute the flour for coconut flour or any other kind of flour ?
Hey Crystal,
I would recommend using a GF flour blend. I hope you love this recipe, please let me know if you give it a try! xTieghan
Loved the cake! This was my first attempt at cake baking and it turned out really well! Lots of good reviews from guests and my husband! Only thing was I couldn’t get mine to look quite as pretty as yours ?
Hey Mary,
Fantastic!! I love to hear that this recipe was a hit, thanks a bunch for making it! xTieghan
Hi! I would love to make this for Labor Day weekend but I’m allergic to dairy! Do you think I could sub dairy free sour cream or another dairy alternative for the cake?
Hey Elan,
I think that should be okay for you to do. Please let me know if you give the recipe a try! xTieghan
Can you make this recipe into cupcakes? if so what do you recommend as far as timing?
Hey Patricia,
Sure, I bet that would work well for you, I would start checking for doneness at 25 minutes. I hope you love the recipe, please let me know if you give it a try! xTieghan
I made this cake the day after it was posted and it turned out just like the pictures – a total showstopper. The swirl effect in the frosting reminded me of “Starry Night.” The yellow cake batter was SO light and fluffy and delicious. And I actually loved that there wasn’t a ton of frosting on it – it didn’t overwhelm the delicate cake.
One thing I will say is that I had a TON of blackberry jam left over and I was generous with it at all stages of the recipe – I think you could easily get away with making half the amount if you didn’t want leftovers of it (or didn’t want to buy all those berries). Also, I refrigerated the cake because of all the butter in the frosting – I unfortunately learned later that buttercream can hang at room temp for a couple days – and that definitely changed the texture of the cake and the frosting. But otherwise delicious and one of the prettiest things I’ve made in a while.
Hey Maura,
Thanks a lot for giving this recipe a try, I am so glad to hear that it was enjoyed!! xxTieghan
Hi,
I have a homemade blackberries jam already, do you think it will be fine if I used that instead? Gracias:)
Hey Bel,
Yes, that would be just fine to use. I hope you love this recipe, please let me know if you give it a try! xTieghan
Can you make this without the lavender?
Hey Johanna,
Yes, totally fine to skip the lavender here. I hope you love this recipe, please let me know if you give it a try! xTieghan
Loved it and got a good response from guests that I served it to. Next time I would definitely try to strain the seeds out of the jam (as they always get stuck in my teeth) and I would try a cream cheese icing instead as I found this one still a little to sweet for me!! But it was Rick and moist and delicious!!
Hey Nelly,
Awesome! I am so glad to hear that this recipe was enjoyed, thanks so much for making it! Have the best weekend:) xTieghan
Could I swap extra light olive oil for the melted coconut oil, or would that change the texture of the cake? Thank you!
I am planning on making this for a bridal shower- can I make the day before? Or is it better to make the day of?
Hey Ann,
You can make the day before, I would save the frosting for the day of:) I hope this recipe was enjoyed, please let me know if you give it a try! xTieghan
Dear Tieghan!
The cake was amazing! we made it for my daughters wedding shower. Made 3 cakes – the third with gluten free flour.
So delicious and beautiful! And everyone wanted more! how often does that happen for cake at a shower!
we did have a tiny bit of trouble telling if it was done – I think due to the jam – but it came out perfect I will post an image to Instagram
Thanks for this recipe posted just in time for us to have a beautiful unique cake at the shower!
– Ann
Hey Ann,
Fantastic!! I love to hear that this recipe was a hit, thanks a bunch for making it! xTieghan
How much jam does this make? Is there ever any leftover? I’m thinking about making extra so I have blackberry and lavender jam just in my pantry for the future!
Hey Josie,
Depending on how much jam you use in the cake, you could very well have some leftover:) I hope you love this recipe, please let me know if you give it a try! xTieghan
Should this cake be refrigerated when not serving? Or is it okay to leave out at room temp?
Hey Brianna,
As long as your kitchen isn’t super warm it should be totally fine in an airtight container on the counter:) I hope this recipe turns out amazing for you, please let me know if you give it a try! xTieghan
My jam doesn’t seem to be thickening is there anything I can do so it sets up ?
Hey Kate,
I would allow it to boil longer:) Please let me know how it turns out! xTieghan
Thanks I turned up the heat and boiled a bit longer and it turned out perfect! My husband said it’s the best cake he’s ever eaten. Another great recipe! Thanks
So glad to hear this:)
Oh my goodness….this cake is so delightful! New staple in my house during blackberry season!
It’s light and not over the top sweet!
Hey Tricia,
Fantastic! I am delighted to hear that this recipe was enjoyed, thanks a lot for giving it a try! Have the best week:) xTieghan
Hi Tieghan,
Can I use unsalted butter for the frosting? The cake looks great!
Thank you!
Hey Emily,
Yes, unsalted butter will be just fine to use! I hope you love this recipe, please let me know if you give it a try! xTieghan
Super easy to make! I know it’s going to be a huge hit for my friends at Bible study.
Hey Mckena,
Fantastic! I am delighted to hear that this recipe was enjoyed, thanks a lot for giving it a try! Have the best week:) xTieghan