1. Melt chocolate and oil over very low heat. 2. Cream butter until light. Add sugar, eggs, and vanilla; beat well. 3. Add melted chocolate to butter mixture and mix well. 4. Sift dry ingredients together, then add them alternately with the buttermilk to creamed mixture, beating well after each addition. 5. Mix the zucchini and nuts into the batter. 6. Pour batter into 2 greased and floured 9" pans. Bake in preheated 350 degree oven for 40 minutes or until cake tests done.
Cool completely; frost with whipped cream or other desired frosting. Cream Cheese Frosting: Cream together the butter and cream cheese until light and fluffy. Slowly add confectioner's sugar until well blended. Use more sugar if necessary, to get a spreading consistency.