combine flour,potato powder,baking soda,salt and pumpkin pie spice in bowl.
add dry ingredients,alternately with the orange juice,beat well after each addition.
fold in the pumpkin,and walnuts.
grease an 8-cup tube mold,sprinkle with the bread crumbs,tapping out the excess.
pour batter into the mold.
cover with double thickness foil,and tie with string,tightly.
place on rack in kettle or steamer.
pour boiling water to half way up the mold,cover kettle tightly.
steam for 2
hours (or) until long skewer comes out clean,when inserted into center...keep the water boiling gently,adding more if need be.
loosen the pudding around the edge,unmold onto antique plate,cool slightly.
spoon about 1/2 of the rich butterscotch sauce over pudding.
serve,cut into wedges and offer the remaining sauce.
note: you may unmold the pudding and cool completely,wrap and freeze...when at 'the end' of your delightful dinner,have the pudding thawed,reheat in a 300 degree oven within its mold for about 30 minutes...you may prepare this and give as two gifts when steamed in two 4 cup molds that have been steamed for 1 1/2 hours.