Very slightly adapted from In a Vermont Kitchen by Amy Lyon and Lynne Andreen
Preheat oven to 375. In a large bowl, sift together the flour, baking powder, baking soda, cinnamon, salt and sugar.
In a medium bowl, mix together the pumpkin, butter, and orange peel. Add the dry ingredients to the pumpkin mixture, and mix until just incorporated. Stir in the raisins and walnuts. Drop dough by tablespoonful onto ungreased baking sheets. Bake 10 minutes, then transfer the cookies to a wire rack to cool completely.
To make the icing: stir in 1 tablespoon of heavy cream into the powdered sugar and cinnamon, and slowly add more until you reach a smooth consistency that you like (some people like thicker icing than others). I generally will add a little over 2 tablespoons to a cup of sugar and whisk well. Ice the cookies when they are cooled completely. The icing will dry nicely on top. These have a rustic look, so don’t worry about being precise with the icing or the shape of the cookie.