Mix together butter, flour and sugar and put into a 9x13 pan. Bake at 350 degrees for 15 minutes. Cool completely. Beat cream cheese with sugar and milk. Add vanilla, mix well. Fold in pineapple by hand. Spread mixture over cooled crust. Mix coconut and butter. Sprinkle evenly over cream cheese layer. Bake at 350 degrees for 20 minutes. Cool completely and refrigerate before cutting and serving.