INGREDIENTS
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cookies:
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3 cups cake flour
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1 tablespoon baking powder
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1/2 teaspoon salt
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1 cup (2 sticks) unsalted butter, softened
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1 cup sugar
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1 large egg plus 1 large egg white, lightly beaten together
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2 tablespoons sour cream
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1 teaspoon vanilla extract
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frosting:
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1/2 cup (1 stick) unsalted butter, softened
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1 pound powdered sugar, sifted
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3 tablespoons milk
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1 1/2 teaspoons vanilla extract
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sprinkles of choice, optional