Adapted from an old recipe in Bon Appetit. The recipe calls for self-rising flour, but you can use one of the many homemade substitutes. I use 1 ½ cups of all-purpose flour plus ¾ teaspoon baking powder, ¼ teaspoon baking soda and ½ teaspoon of salt.
Preheat oven to 350 degrees F. Line two baking sheets with parchment paper.
Soak the raisins and oats in the ¼ cup of hot water for about 15 minutes.
Beat butter until creamy. Add both sugars, egg, and vanilla and beat just until mixed. Add the cinnamon and flour and stir until blended.
Mix in soaked raisin mixture, carrots and nuts.
Drop mounds of dough onto parchment lined baking sheets spacing at least 2 ½ inches apart.
Bake 1 sheet at a time on center rack for 12 -14 minutes or until edges are browned and centers appear set. Let cookies cool on baking sheet for about 4 minutes, then carefully transfer to a wire rack.
Prepare Filling. Beat all the ingredients except for the cream together in a bowl. Gradually add the cream, beating until icing is smooth and spreadable.
Sandwich the icing between two cookies.
Notes
Note: To toast walnuts, spread them on a baking sheet and bake at 350 for about 8 minutes. If you leave the nuts out and you are weighing your flour, you may want to go with 5 ½ oz flour.