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lemon poppy seed cupcake topped with a bright pink swirling frosting

Lemon Poppy Seed Cupcakes with Blackberry Buttercream

Light fluffy lemony cupcakes with a little crunch from poppy seeds topped with a beautiful fresh blackberry buttercream frosting.
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Course: Dessert, dessert cake
Cuisine: Amercian
Keyword: box cake mix, cupcakes with box mix, lemon cake
Prep Time: 10 minutes
Cook Time: 22 minutes
Total Time: 32 minutes
Servings: 18 cupcakes
Author: Laura Franco

Ingredients 

LEMON POPPY SEED CUPCAKES

  • 1 lemon cake mix
  • 4 eggs
  • 1/3 cup fresh lemon juice
  • 1/3 cup canola oil
  • 2/3 cup water
  • 1 tbsp lemon zest
  • 2 tbsp poppy seeds

BLACKBERRY BUTTERCREAM

  • 1/2 pint fresh blackberries
  • 1 cup butter - softened at room temperature
  • 3 cups confectioners' sugar
  • 1 teaspoon cream of tartar

Instructions

LEMON POPPY SEED CUPCAKES

  • Preheat the oven to 350°.
  • Place cake ingredients into a mixing bowl and mix on low speed for 30 seconds.
  • Increase mixer speed to medium-high and mix for 2 minutes.
  • Pour the mixture into a lined muffin/cupcake tin.
  • Bake for 22 minutes or until a toothpick comes out clean.
  • Cool cupcakes at room temperature before frosting.

LEMON POPPY SEED BUTTERCREAM

  • Place blackberries into a small skillet with 1 tbsp water and 1 tbsp honey.
  • Heat on medium until berries break down. Watch them so they do not burn.
  • Remove the berries from the heat.
  • Using a fine mesh strainer, press the berries so the berry juices run into a small bowl.
  • Discard the berry pieces in the strainer and set berry juice aside or in the refrigerator to cool.
  • Add the butter to a mixing bowl and mix until smooth.
  • Mix in cream of tartar and ½ but confectioners’ sugar.
  • Continue to mix in sugar ½ cup at a time.
  • Add 2-3 tbsp of blackberry juice to the buttercream.
  • Transfer the buttercream to a pastry bag with a frosting tip.

Notes

Krazy Kitchen Mom Tips
  • Depending upon the size of the lemons, it will take 2-3 large lemons to yield 1/3 cup.
  • Be sure that the blackberry juice is completely cooled before adding it to the buttercream.
  • Store frosted cupcakes in an airtight container in the refrigerator.
  • You can also freeze unfrosted cupcakes wrapped in plastic wrap for 3-4 months. To thaw, let them sit in the refrigerator overnight or on the kitchen counter. Let them thaw completely before frosting them.
FAQs
WHY DOES THE RECIPE CALL FOR FOUR EGGS WHEN THE BOX MIX INDICATES THREE EGGS?
  • In order to make the cupcakes taste homemade, rather than from a box mix, always add 1 additional egg than the box mix calls for. This works with any type of boxed cake mix.
WHY DO MY CUPCAKES SINK IN THE MIDDLE?
  • This happens for mainly 1 or 2 reasons. First, because you filled the muffin tin with too much batter. Fill each 1/2 to 3/4 of the way. Avoid overfilling them. The second reason is that the cupcakes were overmixed causing too much air during baking. Mixing time is important in making any baked items.