I use to make a very similar version of this recipie at work; other pudding recipies work well too; we tried butterscotch and it was creamy and fabulous!!
This is a great recipe! I made a graham crumb crust instead of the shortbread one and it worked out really well! It was really easy to make, too!
Just wanted to add that you could probably use any flavour pudding/ type of nuts you like for variation to this recipe!