Beat butter and sugar until smooth. Add eggs, one at a time. Stir in zucchini and rum. Mix together flour, walnuts, chocolate, cocoa, baking powder, baking soda, cinnamon, and salt. Stir flour mix and milk into egg mix. Put in well buttered and floured 10" tube pan or ridged pan. Bake 350 50-55 minutes. Cool in pan on rack 15 minutes. Invert and remove. Let cool. Rum glaze: 1 2/3 cup powdered sugar and 3 Tb rum or water mixed together. ----