Mom's Buttermilk Cookies Recipe

Ingredients

• 1/2 cup butter, softened
• 1 cup sugar
• 1 egg
• 2-1/2 cups all-purpose flour
• 1/2 teaspoon baking soda
• 1/2 teaspoon salt
• 1/2 cup buttermilk
• 3 tablespoons butter, softened
• 3-1/2 cups confectioners' sugar
• 1/4 cup whole milk
• 1 teaspoon vanilla extract
• 1/2 cup finely chopped walnuts, optional