A delicious and sweet lemon poppy seed sheet cake is topped with a creamy buttercream frosting flavored with fresh blackberry juice. A wonderful summer cake for dessert or tea time.
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Usually, around this time of year, I am getting excited about fall. Fall is my favorite season and although I am a big believer in “living in the season”, August is about the time of year that falling leaves and pumpkin spice start swirling in my head. This year though, I am trying to soak up every last drop of summer. I am taking every chance I get to spend time outside and of course, making homemade recipes with summer flavors.
If you have been hanging with me for a while, you probably know that our property is overgrown with blackberries. I am not mad about it, except that they grow like a weed in Oregon and are a little hard to keep back.
Luckily, blackberries are my favorite summer berry. Every summer, I am suddenly overwhelmed by the number of blackberries I have to pick, but it gives me the excuse to make delicious summer recipes like these blackberry honey creamsicles or these blackberry milkshakes.
Another one of my favorite summer flavors is lemon. We had lemon poppyseed cake at our wedding and I make this refreshing ginger lemonade all the time during the summer months. Putting my two favorite summer flavors together was an obvious choice! Sheet cakes are so fun and have a gorgeous presentation.
Sheet cake is usually a pretty simple recipe and it cuts into perfect pieces of cake that you can easily pick up and stuff in your mouth. Or eat with a fork like a civilized person, but where is the fun in that?! Like most of my recipes, I had to make this one a few times to get it just right.
The first go around the cake was a little too dense and the buttercream was a little too wet. No biggie, since the flavors were still there I enjoyed some cake and moved on to round two. Once I made a few slight changes, this perfectly sweetened beauty was born.
I have used two different types of equipment to make this cake. A single batch in a 9×13 baking pan lined with parchment is my go-to option and you probably have it in your kitchen right now. You can also use a sheet pan extender, an easy option that creates a very flat sheet cake. Also, if you want to make a bigger cake, you can double the recipe and use a standard sheet pan size and extender.
The cake has that just right lemony flavor and is not overly sweet. Topped with a classic, creamy buttercream frosting sweetened with a fresh blackberry puree. Make this cake for a backyard birthday party, tea time with friends, or just a sweet treat for the family!
Lemon Poppy Seed Sheet Cake with Blackberry Buttercream Frosting
Ingredients
Lemon Poppyseed Cake
- 2 1/2 cups all-purpose flour
- 3 teaspoons baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
- 1/2 cup butter, softened
- 1 1/4 cup granulated sugar
- 4 eggs
- 1 1/2 teaspoons vanilla extract
- 2 tablespoons lemon juice
- 2 tablespoons lemon zest
- 2 tablespoons poppy seeds
- 3/4 cup milk
Blackberry Buttercream Frosting
- 1 cup butter, softened
- 1 1/2 cups powdered sugar
- 2 teaspoons vanilla extract
- 3/4 cup fresh blackberries
Instructions
Lemon Poppyseed Cake
- Preheat your oven to 375 degrees and grease and line a 9×13 baking pan with parchment paper. If you plan on serving the cake within the pan, omit the parchment paper.
- In a medium bow, sift the flour, baking powder, salt, and set aside.
- Using an electric mixer with the paddle attachment, beat the butter until creamy. Gradually add the sugar and beat until light and fluffy.
- Add the egg yolks, one at a time and beat until combined.
- Scrape down the sides of the bowl and add vanilla, lemon juice, lemon zest and poppy seeds. Beat until combined.
- With the mixer one low, add the flour and milk alternately until beat until combined.
- Pour the batter into prepared pan and using a spatula, spread until even in the pan. The batter will be a little sticky and will need to be pushed lightly into the corners of the pan.
- Bake for 25 – 30 minutes or until a toothpick in the center comes out clean.
- Let the cake cool completely before frosting. If you would like to remove the cake from the pan, allow to cool for at least 30 minutes before doing so.
Blackberry Buttercream Frosting
- To make the blackberry puree, place blackberries into a food processor and pulse until completely pureed. Strain the puree through cheesecloth or a fine mesh strainer to remove seeds. If you do not have a food processor, you can mash the blackberries into a strainer over a bowl until you get about 2 tablespoons of puree.
- Using an electric mixer with the paddle attachment, beat the butter until creamy.
- Gradually add the powdered sugar and beat until smooth.
- Add the vanilla extract and blackberry puree and beat until combined.
- Spread the frosting onto a cooled cake. Serve immedietly or store in the refridgerator for up to 7 days. Enjoy!
