These tangy and sweet Lemon Blueberry Cupcakes are irresistibly soft and fluffy, and filled with a homemade blueberry sauce. They’re the best summer dessert topped with beautiful swirls of vanilla and blueberry frosting!
For the Cupcakes
- 2 cups (380g) granulated sugar
- 1/2 cup (118ml) vegetable oil
- 3 large eggs, at room temperature
- 2 lemons, zested and juiced
- 1 teaspoon (5ml) lemon extract, or pure vanilla extract
- 1/2 cup (118ml) sour cream, at room temperature
- 2 1/2 cups (350g) all-purpose flour
- 3 teaspoons (11.2g) baking powder
- 1 teaspoon (5g) salt
- 1/4 cup (59ml) lemon juice, (from the zested lemons)
- 1 cup (236ml) buttermilk, at room temperature
For the Blueberry Sauce
- 18 ounces (510g) fresh Oregon blueberries, rinsed.
- ¼ cup (48g) granulated sugar
- 1 tablespoon cornstarch (or AP flour)
- 3 tablespoons (45ml) water, divided
For the Frosting
- 1 1/2 cups (339g) unsalted butter, cold
- 5 ½ cups (715 g) powdered sugar
- 1 teaspoon (5ml) pure vanilla extract
- 1 tablespoon (15ml) fresh lemon juice (or milk)
- ¼ teaspoon salt
- 2–3 tablespoons blueberry puree (made from blueberry sauce)
For the Cupcakes:
- Preheat the oven to 350°F. Line cupcake pans with cupcake liners.
- In a large mixing bowl, combine the sugar, vegetable oil, eggs, and lemon extract. Beat on medium speed until the eggs and oil are well incorporated, scrape down the bowl as needed. Next, add the lemon zest and the sour cream and beat until well combined.
- Combine the dry ingredients in a separate bowl. Alternate adding half the dry ingredients followed by half of the liquid ingredients (buttermilk and lemon juice) and mix just until the flour starts to incorporate. Use a spatula to scrape down the sides of the bowl and stir the batter from the bottom to the top to ensure it’s well mixed.
- Using a large cookie scoop, divide the batter evenly, filling each liner 2/3 full. Bake at 350°F for 15-18 minutes. Test the cupcakes for doneness by inserting a toothpick into the center of the cupcake. If the toothpick comes out clean, the cupcakes are done. Cool Completely.
For the Blueberry Sauce:
- In a medium-sized bowl, combine the blueberries and sugar and stir to combine. Transfer to a large saucepan, add 2 tablespoons water, and cook over medium-high heat until the mixture starts to bubble and release the juices, stirring often. As the blueberries break down, combine 1 tablespoon water with the cornstarch and stir to dissolve; add to the blueberries and mix to combine.
- Turn down the heat and let simmer to allow the blueberries to soften and further cook down. Cook until sauce starts to thicken; around 10-15 minutes. Stir often so the bottom does not burn. Remove from the heat and cool completely, refrigerate if necessary. The sauce will further thicken as it cools.
- Separate ¼ cup of the blueberry sauce and puree in a food processor or blender until it reaches a smooth consistency. Set aside.
For the Frosting
- Cut the butter into pieces. Using the paddle attachment, whip the butter for 5-7 minutes, scraping down the bowl occasionally, and beating until the butter looks light in color.
- Add 2 cups of powdered sugar and the vanilla extract and mix on low speed until incorporated, then increase the speed to high, and beat for approximately 60 seconds or until well combined. Scrape down the bowl. Add the remaining 3 cups of powdered sugar, lemon juice, and salt. Beat on low until the ingredients start to mix together. Increase speed to high and beat for another 2-3 minutes until it reaches desired consistency.
- Separate out half of the frosting and set aside in a bowl. To the mixer add 2 tablespoons of blueberry puree and mix to combine. If the frosting seems thin or runny, add an additional ½ cup of powdered sugar. Add additional puree to taste.
- Assemble the piping bag. Fit a large piping bag with a large tip and fill it half full with both vanilla and blueberry frosting (see notes for additional tips).
- Remove the centers using a cupcake corer. Save the tops of the cupcakes to the side.
- Use a spoon to fill the center of each cupcake with the blueberry filling. Gently push the top of the cupcake back on top of the filling and frost.
- Buttermilk: Make a homemade buttermilk using milk with either lemon juice or vinegar.
- Sour cream: Use plain or Greek yogurt.
- Fresh blueberries: Frozen blueberries can be used instead. Additional corn starch may be needed to help thicken.
Once frosted, cupcakes can be stored in an airtight container at room temperature for 24 hours. If it’s hot or humid, then I recommend refrigerating in an airtight container. Cupcakes will stay fresh in the refrigerator for 3-4 days. These are best served at room temperature.
The sauce can be prepared 48 hours ahead of time and kept in the refrigerator in an airtight container. The cupcakes are best within the first day or two but can be prepared ahead and kept at room temperature in an airtight container. The frosting can be prepared up to 7 days in advance and kept in the refrigerator in an airtight container. Bring back to room temperature and re-whip in the mixer before using. In this case, add the blueberry puree once it’s rewhipped.
Filling the piping bag:
To assemble a piping bag with 2 different frostings, you can do it a couple of different ways. I find it easier to fill piping bags individually and then use those to squeeze the frosting into the third bag fitted with the tip. Alternatively, you can pipe the frosting onto a large piece of plastic wrap, fold it together and drop it into a piping bag. For a visual tutorial, see the post for these rainbow cupcakes.
- Category: Cupcakes
- Method: Baked
- Cuisine: American
Keywords: Lemon Cupcakes, Blueberry Sauce, Blueberry Frosting