Preheat oven to 350�F. Butter and flour two 9x5x3-inch loaf pans. Beat sugar and oil in large bowl to blend. Mix in eggs and pumpkin. Sift flour, cloves, cinnamon, nutmeg, baking soda, salt and baking powder into another large bowl. Stir into pumpkin mixture in 2 additions. Mix in walnuts, if desired.
Divide batter equally between prepared pans. Bake until tester inserted into center comes out clean, about 1 hour 10 minutes. Transfer to racks and cool 10 minutes. Using sharp knife, cut around edge of loaves. Turn loaves out onto racks and cool completely.
Serve one of these loaves the day you make them. Wrap the other in foil and freeze up to one month so that you'll have it on hand for unexpected company.
Makes 2 loaves.