Start with the Amaro Montenegro in a shaker containing ice, add whiskey to lime juice, add sugar syrup, then bitters, shake it like an MX-5 on the Harbour Bridge. Pour over ice into a fancy glass and consume.
Gwilym and Tom make a devastatingly good Fentimans cola cocktail keg! Take the full time bartending out of your party with a big batch cocktail or punch. If you don't have an ikegger cocktail keg, this is still great to make in a giant bowl!
However, for those wishing to make a single serve: