CRUST: Mix graham cracker crumbs, flour, pecans, brown sugar, and melted butter until all the dry ingredients are damp. Bake at 350 degrees , stirring every 5 minutes until crumbly and fairly dry. Let cool. Divide into three equal parts.
BANANAS:Slice bananas into bowl. Soak in pineapple juice for at least 1 hour before using. Stir occasionally to make sure all slices are coated with juice. (I add a tablespoon of banana flavoring to the juice) My grand kids love to drink the pineapple/banana juice after I am through soaking the bananas.
FILLING: Fix pudding as directed on box. (I add a couple of teaspoons of banana flavoring in the pudding for a stronger banana taste) Mix the cool whip and marshmallows into the pudding. Let set for several hours or the marshmallows will be chewy. (This setting can come after the pudding is assembled.)
ASSEMBLE: Using an 13 X 9 X 2 pan, layer 1/3 of the crumb mixture, 1/2 of the bananas, and 1/2 of the pudding mix, then repeat with the crumb mixture, bananas, and pudding. Sprinkle the final 1/3 of the crumb mixture on top.
NOTE:You may substitute Vanilla Wafers crumbs for the Graham cracker crumbs in the crust. I like to use the Cinnamon Grahams to introduce a slight taste of cinnamon.