In a large bowl, combine sugar, butter, pumpkin, vanilla, eggs, cinnamon, nutmeg, ginger and cloves. Blend well. Add in flour, baking powder and salt. Blend well. Stir in raisins and nuts.
Drop rounded teaspoonfuls, 2 inches apart, onto ungreased cookie sheets.
Bake for 12 to 15 minutes or until barely browned on edges. Remove from cookie sheets immediately and place on cooling rack.
In a medium saucepan, brown the ⅓ cup of butter over medium heat. Stirring constantly, cook until the butter is lightly golden brown. Pour browned butter into a mixing bowl. Add the powdered sugar, vanilla, salt and 2 Tbs. of the milk. With a hand mixer, beat until smooth, adding more milk if necessary to reach the desired thickness. Frost cooled cookies.