caramel cake

INGREDIENTS

• 2 cups plus 2 tablespoons sifted cake flour (not self-rising; sift before measuring)
• 1 teaspoon baking powder
• 3/4 teaspoon baking soda
• 1/2 teaspoon salt
• 1 stick unsalted butter, softened
• 1 cup sugar
• 1 teaspoon pure vanilla extract
• 2 large eggs, at room temperature 30 minutes
• 1 cup well-shaken buttermilk
• 1 cup heavy cream
• 1/2 cup packed light brown sugar
• 1 tablespoon light corn syrup
• Equipment: a candy thermometer