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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.
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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
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!
Nutrition
Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
Did you make this recipe? Please rate & comment below.
Hi– how long will the jam stay good in the fridge? I just got my blackberries and I’m afraid they’ll go bad before I am ready to make the whole cake!
Hey Mikayla,
The jam is good for 2 weeks in the fridge. Please let me know if you give this recipe a try, I hope you love it! xT
Looks delicious! What can I substitute coconut oil with?
Hi Michelle! You could use melted butter! xT
This was surprisingly so delicious and very easy to make! Thank you so much!
Thanks so much for trying out the recipe! Have a wonderful holiday season! xT
One of my favorite cakes recipes I found online. Soo moist!! It stayed moist for long without refrigeration 😊
The only thing is the frosting was a little on the sweet side for me. But the cake was finger licking 😍
Hey Laura,
Wonderful!! I love to hear that you enjoyed this recipe! Thanks so much for your feedback and trying the recipe! Happy Thanksgiving! xT
So excited to try this I’ve never baked with coconut oil before! Can I bake the cake ahead of time and freeze it? Wanting to have this cake for when my sister visits in 5 days but have the itch to bake now :)!
Hey Maddy,
Of course, that will work well for you! I hope you love this recipe, let me know how it turns out! xT
Hi! Do you recommend refrigerating it or leaving it at room temperature if we prep it a day in advance? I also struggled to get my jam to thicken 🙁 Do you by chance have any advice?
Hi Kristin,
You can go ahead and pop it in the fridge:) I would simmer the jam longer until it has reached your desired consistency. I hope you love this recipe! xT
Hi! I love this cake! I’ve made it a few times, but my last time the cake sunk in the middle. What did I do wrong?
Thanks!
Hi Rebecca,
Thanks so much for making this cake!! Sorry to hear it is sinking in the middle. Any chance you are using a glass baking dish? I would recommend using a metal baking pan for this recipe. I hope this helps! xx
Can I substitute strawberries in this recipe?
Hi Brandi! That should work just fine! xT
Hi, can this be made in cupcake form?
Hi Alyssa! I think that should work well! xT
What would be the best way to bake this in a 18×13 sheet cake pan? Would I need to double the recipe and reduce the time? Thank you! So excited to make this for a bridal shower!!
Hi! I don’t think you need to double the recipe to fit it in an 18×13 pan! xT
How can I make this cake a day early without it drying out?
Definitely! xT
Would this work with a different neutral oil instead of coconut? Thank you love your recipes!! Xxx
Yes definitely! You can use melted butter or vegetable oil! xT
I messed up the frosting somehow. When I added the melted cooled chocolate the butter seperated? Otherwise smells great.
Hey! oh I’m sorry about that! Is there anything you did differently? xT
I followed the recipe as written the first time and butter separated for me as well. Icing was also super sweet, going to do a simple whipped topping to lighten the cake as a whole next time.
I made this cake for my friend’s birthday and everyone loved it! I made it with raspberries instead of blackberries. One note, since I used frozen raspberries the ‘jam’ was quite watery and didn’t thicken to a typical jam-like consistency. I think this may have been why the cake too longer to bake too (45 mins). Next time I’ll add cornstarch or arrowroot powder to thicken it up more. Otherwise the cake tasted great!
Hi Renee! Thanks for trying out the recipe! Did you let the jam simmer/boil for a bit? Sometimes that helps to thicken it! xT
I wish I would’ve read your comment earlier because it was so validating. The exact same thing happened to me! I used frozen blackberries and my jam is still really liquidy and my cake also took an extra 10 or so minutes to cook. I also didn’t think to add a shortening until too late but oh well! Try again next time 😊
Really, really good. I decided to do a layered cake, and didn’t have to modify cake recipe to do so. Ty!
Hi Audrey,
Happy Friday!! I am thrilled to hear that this recipe was such a hit! Thanks so much for giving it a try!😎☀️ xT
Wow this cake made my day! So beautiful and the house smells amazing! I had to make it GF for celiac reasons. I substituted Bob Red Mills GF all purpose flour and it turned out perfect!!
Yummmmm
I just did the same thing today! I can’t wait to try it!
Hey Molly,
Happy Friday!!🫐🍓 I love to hear that this recipe was enjoyed, thanks a lot for your comment and making it! xT