Blueberry Cupcakes

Ingredients

For the Topping:

• 6 tablespoons granulated sugar
• 1⁄4 cup dark-brown sugar
• 1 teaspoon cinnamon

For the Cupcakes:

• 1 ⅔ cups cake flour (not self-rising)
• 1⁄4 teaspoon baking soda
• 1 teaspoon baking powder
• ½ teaspoon fine salt
• 1 stick unsalted butter, softened
• ⅔ cup granulated sugar
• 2 large eggs
• ¾ cup sour cream
• 1 teaspoon pure vanilla extract
• 6 ounces blueberries (1 1⁄4 cups)

For the Icing:

• 1 1⁄4 sticks unsalted butter, softened
• 8 ounces cream cheese, room temperature
• ½ teaspoon pure vanilla extract
• 2 ⅔ cups confectioners' sugar, sifted
• 1⁄4 cup high-quality blueberry jam, such as Hero, strained (3 tablespoons)

Instructions

1. 1
   Make the topping: In a small bowl mix together granulated and brown sugars and cinnamon.
2. 2
   Make the cupcakes: Preheat oven to 375 degrees with rack in upper third of oven. Line cups of a standard muffin tin with baking cups. In a medium bowl, whisk together flour, baking soda, baking powder, and salt. With mixer on medium-high speed, beat together butter and granulated sugar until pale and fluffy, 2 to 3 minutes. Beat in eggs, 1 at a time, sour cream, and vanilla, scraping down sides of bowl. Sprinkle blueberries with a little of the flour mixture; set aside. Reduce speed to low, and beat in flour mixture in 3 additions. Fold in blueberries.
3. 3
   Divide batter among baking cups. Add topping, pressing to adhere to batter. Bake until golden and a toothpick inserted in center comes out with moist crumbs attached, about 25 minutes. Remove cupcakes from tin, and let cool completely on a wire rack.
4. 4
   Make the icing: Beat together butter and cream cheese with a mixer on medium-high speed until pale and fluffy, about 2 minutes. Reduce speed to low, and gradually beat in vanilla and confectioners' sugar. Raise speed to medium-high, and beat 1 minute. Spoon jam on top of icing, and without stirring, spoon icing into a disposable pastry bag. Snip off a 3/4-inch opening in tip, and pipe swirled mounds of icing on top of each cupcake. Although best if eaten immediately, cupcakes can be refrigerated up to 6 hours and brought to room temperature 45 minutes before serving.