Ingredients

Lemon Cupcakes: 1¾ cups (218.75 g) cake flour, 1 teaspoon baking powder, ¼ teaspoon baking soda, ½ teaspoon salt, ½ cup (113.5 g) unsalted butter (room temperature), 1 cup (200 g) granulated sugar, 1 tablespoon lemon zest, 2 large eggs (room temperature), 2 teaspoons vanilla extract, 2 tablespoons lemon juice, ½ cup (118.29 ml) whole milk (room temperature)

Blueberry Curd: 1¼ cups (185 g) blueberries (fresh or frozen, unthawed), zest and juice from ½ medium lemon, ¼ cup (50 g) granulated sugar, 1 large egg, 1 large egg yolk, ⅛ teaspoon salt, ¼ cup (56.75 g) cold unsalted butter (cut into about 5 pieces)

Lemon Cream Cheese Frosting: 5 tablespoons (70 g) unsalted butter (room temperature), 3½ ounces (99.22 g) full fat cream cheese (brick style, room temperature), ¼ teaspoon vanilla extract, 1 tablespoon lemon zest, 1¾ cups (210 g) powdered sugar (add extra ¼ cup if needed to thicken), ⅛ teaspoon salt, ½ tablespoon blueberry curd (or substitute milk or heavy cream)

Instructions

Blueberry Curd: Chop the butter into about 5 pats and place in a large non-metal bowl. Set a sieve over the bowl and set aside.

Blueberry Curd: In a medium heavy-bottom saucepan, combine sugar and lemon zest. Rub the zest into the sugar to release oils (optional). Add the egg, egg yolk, and salt, whisking until smooth.

Blueberry Curd: Stir in blueberries and lemon juice. Cook over medium-low heat, stirring constantly, until mixture simmers and thickens enough to coat the back of a spoon (about 10 minutes).

Blueberry Curd: Strain the curd through the sieve into the prepared bowl, pressing to discard skins. Stir in cold butter until melted. Cover with plastic wrap pressed onto the curd surface and refrigerate at least 2 hours to cool and thicken.

Lemon Cupcakes: Preheat oven to 350°F (175°C) and line a muffin pan with paper liners. In a medium bowl, whisk together cake flour, baking powder, baking soda, and salt. Set aside.

Lemon Cupcakes: Using a mixer, beat butter, sugar, and lemon zest on medium-high speed for 3-4 minutes until fluffy. Add eggs one at a time, scraping the bowl after each addition. Mix in vanilla extract.

Lemon Cupcakes: In a small bowl, combine milk and lemon juice. Alternately add the dry ingredients and milk-lemon mixture to the batter, starting and ending with the flour mixture. Mix until just combined.

Lemon Cupcakes: Scoop batter into liners, filling 2/3 to 3/4 full. Bake 17-21 minutes or until a toothpick inserted comes out clean. Cool in pan 10 minutes, then transfer to a rack to cool completely.

Lemon Cream Cheese Frosting: Beat butter and cream cheese on medium speed until combined. Add powdered sugar, blueberry curd (or milk), lemon zest, vanilla, and salt on low speed, then beat on medium for 2-3 minutes until fluffy. Adjust consistency with more powdered sugar or curd as needed.

Assembling and Decorating: Use a cupcake corer or large piping tip to remove the center from each cupcake. Fill each cavity with at least 1 teaspoon of blueberry curd. Frost cupcakes as desired, piping a circle around the opening so the filling shows.

Tips & Variations

Use cake flour for a tender crumb, or substitute with all-purpose flour plus cornstarch if needed.

Fresh or frozen blueberries work well for the curd; stir constantly to prevent clumping or burning.

Press plastic wrap directly on the curd surface to avoid a skin forming while cooling.

Store leftover blueberry curd in a non-metal container to avoid metallic taste.

For a quicker option, substitute homemade blueberry curd with store-bought blueberry jam.

FAQs

Can I use all-purpose flour instead of cake flour?

Yes, you can substitute cake flour by sifting 1 cup of all-purpose flour with 2 tablespoons of cornstarch. This will help mimic the light texture of cake flour for soft cupcakes.

How do I keep the blueberry curd from developing a skin?

Press a piece of plastic wrap directly onto the surface of the curd while it cools to prevent a skin from forming. Store it in a non-metal container for best results and flavor.