The Irish fly-half then set up Howlett to score in the corner with a delightfully executed cross-field kick, adding his fifth conversion to increase Munster's advantage.
They stormed from behind to beat Army and secure this trophy with a third quarter that included two field goals, two touchdowns, a two-point conversion, and two takeaways.
Carr's 67th-minute try for Connacht was scant consolation, particularly as Edinburgh went straight back down the field for Grant to go over, with Paterson's conversion bringing up a total of 27 points for the Scotland full-back.