1) Pierce shortbread w/fork before pouring caramel on
2) Add a little salt to caramel
3) Let layers cool before adding next layer (can use freezer/fridge to secure cooling)
4) Line the pan (spray or parchment or foil)
5) Freeze before cutting (or, put in fridge to prevent crumbling)
6) Can reduce amount of chocolate (or even use a little white chocolate and marble it for effect)
7) Make sure to stir caramel constantly
8) Can cut chocolate with a little cream or butter or even the leftover condensed milk (makes it softer; do a ganache?)
9) Can add a little nuts to shortbread mixture
10) Reduce flour to 1 cup
11) Double and use a 9×13