Michelle Darmody: How to bake Millionaire's Shortbread Squares — and the mistakes to avoid

Millionaire's Shortbread is a layered Scottish dessert made with a shortbread crust, sweet caramel, and topped with a layer of chocolate.
I can only guess that the name for these squares comes from their decadence and richness.
Three contrasting layers are brought together to create the enduring favourite, one soft, one crisp, and one crumbly.