Sprinkle yeast on warm water; stir to dissolve. Add 2tsp. sugar and 1½c. flour and beat well by hand, or 2 minutes with electric mixer at medium speed. Cover and let rise in warm place until bubbly, about 30 minutes.
Meanwhile, cream butter and 1 c. sugar until light and fluffy.
Sift remaining 3 c. flour with salt, cinnamon, cloves, mace and nutmeg.
When yeast mixture is bubbly, add eggs to creamed butter and sugar and beat well. Combine with yeast mixture. Add remaining dry ingredients (flour, salt and spices), a little at a time, beating with spoon after each addition. Beat until smooth.
Stir in raisins, citron and nuts. Pour into well greased and floured 10″ tube pan. Cover and let rise in warm place until doubled, about 1½ hours.
Bake in moderate oven (375°) 1 hour. Cool in pan 5 minutes; turn out on rack to finish cooling. While faintly warm, spread with Confectioners Sugar Frosting.