Combine dates, water & oil or shortening. Let cool. Combine the baking soda with the flour & mix well. Add the brown sugar, baking powder, vanilla, salt & nuts to the date mixture. Mix well. Gently fold in the flour & baking soda mixture. If too dry, add a little more water. Bake in greased muffin pans at 160ºC for 25 minutes, or until cooked through.