for the Cupcakes
1 3/4 cups all-purpose flour
1 1/2 teaspoons baking powder
3/4 teaspoons table salt
1 cup granulated sugar
1 1/2 sticks unsalted butter, softened but slightly cool, cut into 12 pieces
3 large eggs
3/4 cups milk
1 tablespoon lemon zest
1 1/2 teaspoons lemon extract
for the mousse filling
1 pint blueberries (fresh or frozen)
1/4 cup granulated sugar
1/2 cup heavy cream
1/2 teaspoon whipped cream stabilizer
pinch of salt
for the frosting
1/2 cup blueberries (fresh or frozen)
1/4 cup granulated sugar
1 tablespoon corn starch mixed with 2 tablespoons of water
8 ounces (1 package) cream cheese, softened to room temperature
1 stick unsalted butter, softened to room temperature
3 cups confectioners sugar
For the cupcakes: Preheat oven to 350F. Line a muffin pan with paper baking cups and set aside.
In the bowl of a stand mixer, combine the flour, baking powder, salt, and sugar on low speed. Add the butter, 1 piece at a time, and combine until the mixture resembles coarse sand. Add the eggs, 1 at time, and mix until fully combined. Add the milk, the lemon extract and the lemon zest, increase the speed to medium, and mix until the batter is light, fluffy and free of lumps.
Fill the lined muffin cups three-quarters full, being careful not to overfill. Bake until a toothpick inserted in the center of the cupcake comes out clean, about 12-15 minutes. Cool the cupcakes in the pan for 5 minutes, then transfer to a wire rack to cool completely.
Make your filling and frosting (some ingredients overlap): Place the blueberries and the sugar in a small sauce pan over medium heat. Macerate and let the blueberries become soft and the sugar completely melt. Transfer to a food processor and pulse until smooth. Return to the sauce pan and add corn starch slurry and bring to a boil until the mixture starts to thicken. Remove from the heat and let cool completely. In the bowl of a stand mixer, whip the heavy cream with the whipped cream stabilizer. Fold together gently as not to deflate. Refrigerate while you make the frosting.
To make the frosting: In the bowl of a stand mixer, combine the cream cheese and butter. Add the blueberry mixer… it will be very blue! Add the sugar and beat until smooth.
To assemble: Insert a small knife at a 45 degree angle about 1/8 inch from the edge of each cupcake and cut all the way around, remove a cone of cake (or use a cupcake corer, if you have one). Cut away all but the top 1/4 inch of the cone; leaving only a small disk of cake which will be used to top the cupcake. With a small spoon, pour in 2 tablespoons of the blueberry mousse into the hole (alternatively, you can use a piping bag with no tip). Top with the disk. Frost liberally with the blueberry frosting.
Keep refrigerated until almost ready to serve.