Lemon Poppy Seed Cupcakes with Blackberry Frosting (2024)

4.34 from 3 votes

Lemon Poppy Seed Cupcakes

• 1 ½ cups all-purpose flour
• 1 teaspoon baking powder
• ½ teaspoon baking soda
• ¼ teaspoon salt
• ½ cup unsalted butter softened to room temperature
• 1 cup white sugar
• 2 tablespoons lemon zest*
• 2 large eggs
• 1 teaspoon vanilla extract room temperature
• ⅔ cup sour cream room temperature
• 3 tablespoons lemon juice* freshly squeezed
• 1 ½ tablespoons poppy seeds

Blackberry Frosting*

• 1 ½ cups blackberries fresh or frozen
• 1 cup unsalted butter softened to room temperature
• 4 cups powdered sugar
• ¼ teaspoon salt
• 1 tablespoon cream or cream if needed

US Customary - Metric

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 ½ of the sour cream followed by about ½ 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 ⅔ 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 ½ 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 ½ 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 ½ 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.