Blueberry Cupcakes with Lemon Custard Filling

The one good thing about being seen last by your large animal vet, is that when they get special goodies along the day, you get to reap the reward of all the extra – it doesn’t hurt that we’re good family friends as well. During one of Mike’s most recent stopovers, he added an overflowing container of blueberries to our smorgus-board of food. Knowing full well that we were not going to be able to eat of these before they went bad, I decided to whip together a batch of these delicious blueberry cupcakes I had made a few years back! They were a total hit then and I could only imagine how good they would taste with these farm fresh, local blueberries.

I went all out on these babies, adding a homemade lemon-curd filling and a lemon mascarpone frosting. Let’s just say no one was complaining that I stole the container of blueberries when I rewarded them with these the next day! Stay tuned for another special concoction from one of Mike’s other contributions.




Blueberry Lemon Custard Cupcakes

Course Dessert
Cuisine American
Servings 24


Blueberry Cupcake

  • 2 cups plus 6 tablespoons all-purpose flour
  • 2 teaspoons baking powder
  • 1 teaspoon salt
  • 3 cups fresh blueberries
  • 1/2 cup sour cream
  • 1/2 cup whole milk
  • teaspoons vanilla extract
  • 3/4  teaspoon pure lemon extract
  • 1 teaspoon lemon zest
  • 1 cup 2 sticks unsalted butter, room temperature
  • 1 1/2 cups white sugar
  • 4 large eggs

Lemon Curd

  • 1 cup unsalted butter
  • 1 cup lemon juice
  • zest of one large lemon I used 4
  • 1 1/2 cup granulated sugar
  • 2 teaspoon cornstarch
  • pinch of salt
  • 12 large egg yolks

Lemon Mascarpone Cream Frosting

  • 1 pound mascarpone cheese
  • 2/3 cup lemon curd
  • 2 cups heavy cream
  • 7 Tb sugar


Blueberry Cupcakes

  1. Preheat oven to 350°F. Prepare muffin tin with cupcake papers or reusable liners. 

  2. Sift dry ingredients into medium bowl. Transfer 1 tablespoon flour mixture to larger bowl. Add fresh blueberries and toss to coat them with flour. Set remaining flour mixture and blueberries aside.

  3. Stir whole milk, sour cream, vanilla extract, lemon extract and lemon zest in small bowl.

  4. In the bowl of a stand mixer, cream butter and sugar, until pale yellow and very fluffy, about 5 minutes. Beat in eggs one at a time, until well combined. Mix in flour mixture alternately with milk mixture, starting and ending with flour mixture. Stir until just combined. Gently fold in blueberries. Divide batter equally among cupcake cups.

  5. Bake cakes until toothpick inserted into center of a couple cupcakes comes out clean, about 20 minutes. Cool in pans on racks for about 10 minutes, then put onto racks until completely cool.

Lemon Custard

  1. Melt the butter in a medium sauce pan over medium-low heat.  Remove from heat and add the lemon juice and zest.
  2. Mix together the sugar, salt and cornstarch and add it to the pan.  Whisk in the egg yolks until smooth and return to heat. Cook over medium-low heat for roughly 10 minutes until the mixture has thickened and coats the back of a spoon. Do not allow the mixture to boil.
  3. Once thickened, strain the mixture though a fine mesh strainer into a large bowl. Allow to chill in the refrigerator completely before using.

Lemon Mascarpone Frosting

  1. Beat the sugar and cream to soft peaks in your mixer.
  2. Combine the mascarpone and lemon curd in a separate bowl and mix. Add the cream to the mascarpone mixture. Gently fold to combine, take your time and be gentle. If the mixture is overworked it can separate or look grainy. To fix this add several tablespoons of heavy cream and mix with the spatula until smooth again.


  1. First measure out the 2/3 cup of lemon curd for the frosting and set aside. After the cupcakes are finished cooling, cut a cone shape out of the middle and remove the tops and put a tablespoon or so of lemon curd in the hole. Place the tops back on (you may have to trim the cone a bit to get it to fit). Lather with frosting and enjoy!


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