A combination of my three loves. Frozen dairy products, rich caramel, and delicious, delicious rum.
A few notes: I tried the recipe with both salted and unsalted butter and couldn't tell a difference in taste, however I did notice a big difference when I used dark brown sugar as opposed to light so just be wary.
And as with any alcoholic recipe feel free to add or remove as much as you'd like. —Matthew Wickham