Chocolate Zucchini Rum Cake

1 cup butter, at room temperature
2 cups granulated sugar
3 large eggs
2 cups shredded, unpeeled zucchini
1/3 cup rum or brandy or water
2 1/2 cups all-purpose flour
1 cup chopped walnuts
1 cup semisweet chocolate bits
1/2 cup cocoa powder
2 1/2 teaspoons baking powder
1 1/2 teaspoons baking soda
3/4 teaspoon cinnamon
1 teaspoon salt
1/4 cup milk

Heat oven to 350 degrees F. Butter well and flour a 10-inch tube pan.

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 mixture and milk into egg mixture. Pour into pan. Bake for 50 to 55 minutes. Cool in pan on rack 15 minutes. Invert and remove. Let cool.

Rum Glaze:
1 2/3 cups confectioners' sugar
3 tablespoons rum

Mix together until smooth.