• 2 1/2 cups sifted all-purpose bleached flour
• 1 1/2 teaspoons baking powder
• 1/2 teaspoon baking soda
• 1/2 teaspoon salt
• 2 sticks unsalted butter , softened
• 1 1/2 cups granulated sugar
• 3 large eggs
• 1 teaspoon vanilla extract
• 1/2 cup buttermilk

• 2 cups firmly packed brown sugar
• 1/4 teaspoon salt
• 1 cup whole milk
• 2 tablespoons unsalted butter

To make cupcakes, preheat oven to 350°. Line muffin pans with 16 to 18 baking cups. Sift flour, baking powder, baking soda, and salt together in a large bowl. In a separate bowl, beat butter with electric mixer until creamy, about 30 seconds. Add sugar, 1/2 cup at a time, and beat until mixture is fluffy and has lightened in color, about 2 minutes. Add eggs, 1 at a time, and vanilla, beating for 15 seconds after each addition. Add flour mixture to butter mixture in thirds, alternating with 2 additions of buttermilk (1/4 cup each). Beat batter with a rubber spatula just 2 to 3 strokes after each addition. Fill cups to 3/4 of an inch from top. Bake until a toothpick comes out clean, 20 to 24 minutes. Cool before icing.

To make icing, combine sugar, salt, and milk in a saucepan and bring to a boil over medium-high heat, stirring occasionally. Continue to boil until 1/4 teaspoon of syrup forms a soft ball when dropped into a bowl of ice water, or until a candy thermometer reaches 232°. Remove pan from heat and stir in butter until melted. Allow caramel to cool until lukewarm. With electric mixer on high speed, beat until smooth and lighter in color, about 4 minutes. Spread on cupcakes.