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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.

Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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.

Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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.

Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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.

Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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!

Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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.

Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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.

Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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.

Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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.

Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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!

Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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

Prep Time 30 minutes
Cook Time 30 minutes
Total Time 1 hour
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.

Ingredients

Blackberry Lavender Jam

Blackberry Cake

Vanilla White Chocolate Frosting

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!
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Swirled Blackberry Lavender Sheet Cake | halfbakedharvest.com

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Comments

    1. Hi Haley,
      I leave them, but if you prefer to do that it’s totally fine! I hope you love this recipe, please let me know if you give it a try! xTieghan

  1. 5 stars
    This cake was everything I hoped it would be, and then some! We were feeling extra light so I went with a stabilized whipped cream for the frosting instead. So so yummy, not to mention, beautiful! Thank you for the recipe

  2. Hi, this looks so beautiful and I’m planning on making it for my Birthday on Sunhat.
    I have a preference towards cream cheese frosting and thought it would pair deliciously with this. I’m wondering if you have a recipe for cream cheese frosting to share?

    1. Hi Jocelyn,
      I don’t have a cream cheese frosting specially for this recipe, but if there is a recipe that you enjoy I’m sure it would work well! Let me know if you give it a try! xTieghan

  3. QUESTION! I’m making this a day in advance. I saw you replied to someone about adding the frosting the day of but, I want to know if I can make the frosting in advance as well and add it the day of?

    1. Hi Sammi,
      Sure, that would be just fine for you to do! I hope you love this recipe, please let me know if you give it a try! xx

    1. Hi Marwa,
      You can use any other neutral oil or butter in place of the coconut oil. Please let me know if you have any other questions! xx

  4. This looks delicious! Would it be okay to omit the lavender (due to an allergy) or would you substitute it with something else?

    1. Hi Megan,
      Totally fine to omit the lavender:) I hope you love this recipe, please let me know if you give it a try! xx

  5. 5 stars
    I made this for my birthday yesterday and it was absolutely delicious! I’m a massive fan of blackberries and lavender but I wouldn’t have thought to put them together in a cake. This cake is delightfully light, fruiting, and fun. I followed the recipe exactly, just adding some extra lavender to the top of the iced cake – I found the lavender taste to be just a hint otherwise. I also added edible flowers which paired beautifully with the swirled jam! The cake received many compliments from my friends and I’m excited to make this for others in the future 🙂

    1. Hi Emily,
      Happy Birthday!! I am so glad to hear that this recipe was enjoyed, thanks so much for making it and sharing your feedback:) Hope you are having a great week! xx

  6. This was so amazing. I just made it tonight and served some to my yoga friends-we call this yoga cake now because of the pleasant lavender aroma and flavor

  7. 5 stars
    This cake was delicious!! A big hit! I did have leftover jam, how long do you think it will be good for? Thanks!

    1. Hey Melissa,
      Fantastic!! I love to hear that this recipe was a hit, thanks for trying it out! I would say the jam is good for 1 week in the fridge. xTieghan

    1. Hi Sandra,
      Sure, that will work well for you! I hope you love this recipe, please let me know if you give it a try! xx

  8. Hi there! I plan to make this for my daughter’s first birthday party next week. (The theme is “Berry 1st Birthday” so it fits well!). There will be some kiddos under a year there, so I was thinking of substituting the honey for sugar. Do you think that would work Tieghan? Thanks in advance!

    1. Hi Claire,
      I would use maple syrup in place of the honey:) I hope you love the recipe! Happy Birthday to your daughter! xx

      1. Im not sure what went wrong … my cake probably Has half the rise of yours ? the only substitute I made was oat milk and and dairy free Greek yoghurt for the sour cream (daughter has diary allergy) do you think that would have affected the rise?

        1. Hi Philippa,
          Thanks so much for trying the recipe, so sorry to hear you had issues! I wouldn’t think either of those would be a rising issue. Did you check the expiration date on your baking soda and powder? That could have been it. Let me know! xx

      2. Hi Tieghan – thanks for your reply on the maple syrup. It worked well! The jam was quite runny with the syrup, so I added 1 tbsp of cornstarch mixed into a 1/4c water, and it thickened it up just enough.

        I made 2 of the cakes for the 1st birthday party, and it was a hit! I don’t think I’ve ever received so many compliments on a cake. I was looking for a classic recipe with a twist that perhaps we’d want to recreate each year for my daughter’s birthday, and we definitely found it. Thank you so much. ?

        1. Hi Claire,
          Happy Labor Day! Thanks so much for making this recipe and sharing your feedback! So glad it was enjoyed:)

    1. Hi Marie,
      Sure, that will work well for you, just reduce your bake time:) I hope you love this recipe, please let me know if you give it a try! xx

  9. 5 stars
    This is honestly the best cake I’ve ever had!! And surprisingly easy to make! I literally texted my mom SOS COME OVER THE CAKE IS SO GOOD.. to which she indeed drove over immediately ? 10/10 recommend!!!

    1. Hi Janae,
      Happy Monday! Thanks a lot for trying this recipe out, I am so excited to hear that it was a hit! xx