Butter a 6-cup loaf pan. Dust it with fine, dry bread crumbs, then tap out excess crumbs. Sift together the flour, baking powder, mace, and salt. Set aside. Mix lemon rind and juice, and set aside. In a large mixer bowl, cream the butter. Add vanilla and sugar, beating well. Beat in the egg yolks. On low speed, add the sifted dry ingredients alternately with the whiskey, beating after each addition only until incorporated. Stir in lemon rind and juice, candied orange peel, raisins, caraway seeds, and pecans. In a small bowl, beat the egg whites until they hold a shape but are not stiff and dry. Fold them into the batter. Turn batter into prepared pan and smooth the top. Then use spatula or spoon to form a shallow trench lengthwise down the middle of the cake. (This makes top of cake more level when baked.) Bake at 350, on a rack 1/3 up from bottom of oven, for 1 1/4 hours or until cake tests done. Be careful not to under-bake. While baking, if the cake begins to darken too much, cover it loosely with foil. As soon as cake is done, remove from oven and spread softened butter over the top. Let the cake stand in the pan on a rack for about 20 minutes. Then invert onto another rack, then back onto first, so that cake cools upright without the pan. Wrap and refrigerate or freeze before slicing.