Preheat oven to 350°. Grease one or more cookie sheets. Using an electric mixer, cream together 1/2 cup butter, shortening, and sugar in a bowl until fluffy. Add eggs and beat until mixture is light in color. Add buttermilk. Sift together flour, baking soda, salt, baking powder, ginger, nutmeg, cinnamon, cloves and allspice; stir into creamed mixture. Fold in oatmeal, raisins, walnuts and 1 teaspoon vanilla, blending well. Drop by rounded teaspoons onto cookie sheet. Bake for 12 to 15 minutes. Drizzle with Brown Butter Icing. Makes About 5 dozen cookies.
Brown Butter Icing
In a small saucepan heat 1/2 cup butter over medium heat until golden brown, stirring occasionally. Remove saucepan from heat; stir in 3 cups sifted powdered sugar and 1 teaspoon vanilla. Stir in enough water (3 to 4 tablespoons) to make an icing of drizzling consistency. Drizzle on warm cookies.