Millionaire shortbread or caramel slice?

Is this a Scottsh thing, or do you have it in other places? It's a layer of caramel on top of a shortbread base, topped with chocolate. On holidays with my closest friend, we pay almost as much attention to this product as we do beer. If we find a good source, it tends to be a daily purchase, and it never lasts long. The joy is in finding an even better one than the last one.