In a bowl, mix peanut butter, sugar and butter. Stir in egg. Add milk and molasses. Stir in remaining ingredients. Grease and flour a 1 1/2 quart steamed pudding mold or soufflé mold. Fill with pudding mixture and cover loosely with a piece of greased foil. Preheat oven to 350 degrees. Place a pan of water into the oven. Place pudding into water and bake for 1 hour. Cool in pan for 5 minutes. Tap to loosen and invert onto serving platter. Serve warm with vanilla ice cream, whipped cream, hard sauce or custard sauce.