In mixing bowl, cream butter and sugar.Add eggs, one at a time, beating well after each addition. Stir in vanilla. Combine the dry ingredients; add to creamed mixture alternately with pumpkin, beating just until combined. Pour into two greased and floured 9-in.x 5-in. x3-in. loaf pans.
Bake at 350f for 65-70 minutes or until a tooth-pick inserted near the center comes out clean. Cool for 10min. before removing from pans to wire racks to cool completely.
For sauce, comebine brown sugar, cream, corn syrup and butter in a saucepan. Bring to a boil over medium heat, stirring constantly. Reduce heat; cook and stir 5min. longer. Remove from the heat; stir in walnuts and vanilla. Serve warm over the cake. 1-2/3 cups of sauce.