Calculating hh:mm between two times that span midnight

or simply format the time cells as Custom, [h]:mm
(This is the 24 hour clock format but recognising that something can run for longer than 24 hours or past the midnight date change)
then add 24:00 to the later time
then subtract the earlier time

e.g.
[A1]22:43
[B1]30:00
[C1]=B1-A1
[Answer] 7:17

Easy peasy, lemon squeezy