For the cupcakes:
2⅔ cups all-purpose flour
2¾ teaspoons baking powder
1 teaspoon salt
14 tablespoons unsalted butter, at room temperature
1 cup plus 2 tablespoons granulated sugar
½ cup light brown sugar
2 large eggs plus 3 large egg yolks
1 tablespoon vanilla extract
¾ cup plus 2 tablespoons buttermilk
1 tablespoon pure maple syrup
1¾ cups fresh blueberries, rinsed and dried
For the caramel:
¼ cup heavy cream
Pinch sea salt
¼ teaspoon pure vanilla extract
¼ cup maple syrup
For the frosting:
12 ounces cream cheese, chilled
½ cup (1 stick) unsalted butter, at room temperature
4 cups confectioners’ sugar, sifted
2½ teaspoons maple extract
To make the cupcakes, heat oven to 350º. Line cupcake pans with paper liners. In a medium bowl, whisk together the flour, baking powder and salt.
Add the butter and sugars to the bowl of an electric mixer fitted with the paddle attachment. Beat on medium-high speed until light and fluffy, 2-3 minutes. Add the eggs and yolks one at a time, beating well after each addition, and scrape the sides and bottom of the bowl as needed. Mix in the vanilla.
In a liquid measuring cup, whisk together the buttermilk and maple syrup. With the mixer on low speed, alternately add the dry and wet ingredients in 2-3 batches, starting and ending with the flour mixture. Mix each addition until just incorporated. Using a spatula, gently fold in the blueberries.
Divide the batter between the prepared liners, then bake for 18-20 minutes, until a toothpick inserted in the center comes out clean. Allow to cool in the pans for about 5 minutes, then transfer to a wire rack to cool completely.
While the cupcakes are baking, make the caramel. In a medium saucepan, heat the cream and salt over medium heat until bubbles just begin to form around the edges. Stir in the vanilla and maple syrup and bring the mixture to a boil. Reduce heat to medium. Stir constantly with a rubber spatula until the mixture reaches 235-240ºF on a candy or infrared thermometer. Set aside to cool slightly (the caramel will thicken as it cools).
To make the frosting, combine the cream cheese and butter in the bowl of an electric mixer fitted with the paddle attachment. Beat on medium-high speed for 2-3 minutes or until light and fluffy. Add the sugar and mix on low speed until just combined. Increase speed to medium-high and continue mixing for 2-3 minutes. Blend in the maple extract.
Frost the cupcakes as desired, then drizzle with the caramel sauce.