Preheat oven to 350 degrees. Combine flour, baking soda and salt; stir to mix well. In the bowl of an electric mixer, beat together shortening, vanilla, sugar, mashed bananas, and eggs. When well beaten, gradually add the flour mixture. Mix only until combined. Stir in the banana liqueur and the chopped nuts. Butter and flour a loaf pan. Bake for 65-70 minutes. Remove from oven and allow to sit for several minutes. Run a bread knife around edges of loaf pan to free it from sides and remove from pan. Rub the top of the still-warm loaf with a pat of butter to soften and glaze the top, if desired. Serve with whipped cream cheese spread on each slice.