Lemon Poppy Seed Cupcakes with Blackberry Frosting

4.34 from 3 votes

I may receive compensation in the form of payment or products to supplement my posts, but all opinions remain my own. Read our disclosure policy.

Moist and tender, these lemon poppy seed cupcakes are bursting with a fresh lemon flavor and filled with tiny, crunchy poppy seeds. The blackberry frosting tastes like biting into fresh berries, and the beautiful color combination makes these absolutely stunning.Lemon poppy seed cupcakes on a wire cooling rack.

I wanted to make a new cupcake recipe for spring, and to be totally honest, I was a little tired of the same old cupcake recipes. So these lemon cupcakes with blackberry frosting were born. Lemon desserts are so perfect for spring because of the bright, sunshiney flavor, and I always feel that tart citrus goes so perfectly with a moist, buttery cake crumb. The sweet blackberry buttercream is beautiful with its deep purple color, and because it’s made with real berries, you end up with the most delicious flavor.

For the Lemon Poppy Seed Cupcakes

These cupcakes are moist, flavorful and have the perfect amount of lemon. We’re using real butter for flavor, and to create that fluffy cupcake texture. Then sour cream keeps the cupcakes soft and tender. For the lemon flavor, we’re using both lemon zest and fresh lemon juice. Always wash the lemons first to remove any wax on the outside, then zest before juicing. When baking, make sure that you use fresh lemon juice instead of the stuff from the bottle to ensure your cupcakes turn our tart and sweet, instead of sour and bitter.

Cupcake on its side with a bite taken out of it.

For the Frosting

If you wanted to keep things simpler, you could frost these cupcakes with a cream cheese frosting instead, but I think the blackberry frosting is definitely worth the effort. The process of making the frosting is pretty much identical to how I make other berry frostings – like my raspberry or strawberry frostings. First, you’ll puree the berries in a blender or food processor, then push the puree through a metal sieve to remove the seeds (this takes a bit of effort because you do need to push it through). Then you boil up the puree to remove the excess liquid. It will gently simmer for about 10-20 minutes, or until its thick like jam. Note that if you really wanted to save time, you could use store-bought blackberry preserves. I do find that the flavor is better when you use real berries.

Then you’ll make the frosting as you would a normal buttercream – beating the butter until smooth, then beating in the powdered sugar and blackberry puree.

Cupcakes with blackberry frosting on a cooling rack, shot from above.

The soft, buttery cupcake crumb, fresh lemon flavor and crunchy poppy seeds make these the perfect lemon poppy seed cupcakes. Not only is the blackberry frosting beautiful to look at, but the fresh berry pairs with the lemon perfectly and really takes the flavor to another level.

Or for more lemon recipes for spring, be sure to try:

Lemon poppy seed cupcakes on a wire cooling rack.
4.34 from 3 votes

Lemon Poppy Seed Cupcakes

Note that if you really wanted to save time, you could use store-bought blackberry preserves. I do find that the flavor is better when you use real berries. 
Prep: 45 minutes
Cook: 18 minutes
Cooling: 45 minutes
Total: 2 hours
Servings: 14 cupcakes
Want to save this recipe?
Just enter your email and get it sent to your inbox! Plus you'll get new recipes from us every week!
Please enable JavaScript in your browser to complete this form.


Lemon Poppy Seed Cupcakes

  • 1 1/2 cups all-purpose flour
  • 1 teaspoon baking powder
  • 1/2 teaspoon baking soda
  • 1/4 teaspoon salt
  • 1/2 cup unsalted butter, softened to room temperature
  • 1 cup white sugar
  • 2 tablespoons lemon zest*
  • 2 large eggs
  • 1 teaspoon vanilla extract, room temperature
  • 2/3 cup sour cream, room temperature
  • 3 tablespoons lemon juice*, freshly squeezed
  • 1 1/2 tablespoons poppy seeds

Blackberry Frosting*

  • 1 1/2 cups blackberries, fresh or frozen
  • 1 cup unsalted butter, softened to room temperature
  • 4 cups powdered sugar
  • 1/4 teaspoon salt
  • 1 tablespoon cream or cream, if needed


Lemon Poppy Seed Cupcakes

  • Preheat the oven to 350F degrees and line 2 muffin pans with liners. You'll end up with about 14 cupcakes in total.
  • In a large bowl sift together the flour, baking powder, baking soda and salt. Give them a whisk.
  • In a separate large bowl, beat the butter, sugar and lemon zest until fluffy.
  • Beat in the eggs and vanilla extract.
  • With the mixer on low speed, beat in about 1/2 of the sour cream followed by about 1/2 of the flour mixture. Turn off the mixer and scrape down the sides of the bowl.
  • Repeat the process with the rest of the sour cream and flour mixture.
  • Gently fold in the lemon juice and poppy seeds.
  • Spoon the batter into the prepared muffin pans filling each about 2/3 full. You should get about 14 cupcakes.
  • Bake 1 tray at a time on the middle rack of the oven for 16-20 minutes, or until the tops look set and an inserted toothpick comes out clean. Cool in the pan for at least 10 minutes, then continue cooling on a wire rack.

Blackberry Frosting*

  • Add the blackberries to blender or food processor and blend until smooth.
  • Press the puree through a sieve to remove the seeds. I typically do about 1/2 at a time and use the back of a metal spoon to push it through.
  • Transfer the seedless puree to a small-medium saucepan over low heat. Bring the mixture to a gentle simmer while stirring occasionally for 10-20 minutes, or until the puree is thick like jam. Remove from the heat and cool completely. You should have about 2-4 tablespoons in total.
  • In a large bowl, beat the butter until soft.
  • Turn the mixer down to low speed and beat in 2 cups powdered sugar and the salt.
  • Beat in 2 tablespoons of the thick, cooled puree.
  • Beat in the rest of the powdered sugar about 1/2 cup at a time, adding in a little more blackberry puree or cream as needed.
  • Transfer the frosting to a piping bag (I used a 1M tip) and frost the cupcakes, or frost with a knife.


  1. You will need 1-2 medium sized lemons for this recipe. Zest the lemons first before squeezing the juice. Do not use lemon juice from the bottle because it is too sour and bitter.
  2. If you'd like a thin layer of frosting for each cupcakes instead of piping on the frosting, feel free to 1/2 the frosting recipe.
  3. Because the puree needs to cool fully before moving on with the frosting, I often make the blackberry puree first. Then make the cupcakes. By the time the cupcakes and baked and cooled - the reduced blackberry puree should be cooled and you'll be ready to make the frosting. 
  4. Instead of using fresh/frozen blackberries and boiling them down, you could use blackberry preserves from the grocery store. You will need 3 tablespoons total. 
  5. I do not recommend doubling this recipe, as it leeds to over mixing the batter which can cause the cupcakes to be tough or sink in the middle.
  6. Storage and Make-Ahead Tips: I recommend making these cupcakes the day you plan to eat them. Store in an airtight container at room temperature for up to 6 hours, or in the fridge for up to 3 days. If you'd like to make the cupcakes the day before, make the cupcakes and store them in an airtight container at room temperature. Make the puree, cool it fully and store in an airtight container in the fridge. Then make the frosting the day you plan to serve the cupcakes. 
  7. Nutrition information is based off 1 cupcake with frosting. 


Calories: 462kcal, Carbohydrates: 61g, Protein: 3g, Fat: 24g, Saturated Fat: 14g, Cholesterol: 90mg, Sodium: 147mg, Potassium: 109mg, Fiber: 1g, Sugar: 49g, Vitamin A: 769IU, Vitamin C: 6mg, Calcium: 56mg, Iron: 1mg
Like this recipe? Rate and comment below!


You Might Also Like

Leave a comment

Your email address will not be published. Required fields are marked *

Recipe Rating


  1. 4 stars
    These were so good!! The cupcakes are a bit dense but so moist with a great lemony flavour. The icing was not too sweet which I really loved but I found it to have not much flavour so I would recommend adding a little extra salt, some vanilla extract and a squeeze of lemon.

  2. The cake itself was great! The icing fell flat. I used a good half cup of blackberry puree, and the blackberry flavor just didn’t come through… was barely there…. what I did have was a fluffy, super sweet and greasy frosting. Was really hoping for more.

    1. Hi Niki,

      You won’t taste the sour cream in the cupcakes. That being said – plain, Greek yogurt (unsweetened) works well as a substitute.

  3. 5 stars
    These Lemon Poppy Seed Cupcakes were absolutely delicious. They were definitely a
    hit for a Birthday Luncheon. I received so many complements. This will be my go-to lemon cupcake recipe.
    I used 20 0z of blackberries but the flavor was faint. I was hoping it had a stronger blackberry flavoring. The color complimented the cupcake.
    Fiona, would you suggest using a blackberry flavoring?
    All & All they weere a plus!

  4. 4 stars
    Followed this to a T. Almost too precisely! I found the cupcakes themselves to be extremely light and fluffy. Super yummy batter recipe. The icing was odd…. it just tasted like sugared butter? But not in a good way like butter cream icing. I double blended and puréed the blackberries to make sure they were delicious & smooth for the broiling process. You can taste them but not enough. The icing is very over powered by the butter.

    1. 2-4 tablespoons. Start with 2 tablespoons, and add a little more as needed. This will depend a bit on how thick your preserves are. Happy baking!