Converting mqtt value from minutes after midnight to hours and minutes

I have a tasmota pool control that handles the timer for the filter, heat, etc. I use a timer (timer1) to trigger a rule that starts the pump and another timer (timer2) to trigger a rule to shut the pump off. I can set these timers via HA front end but there are some occasions where I set them from the GUI on the tasmota. The issue with this is that then the dashboard in HA doesnt reflect the correct timer setting.
I have figured a way to have the tasmota send an MQTT message showing the new time but all it does is send it as minutes after midnight that timer is set to. ie: 08:00 would be sent by mqtt as 420. Is there a way that i can convert that number into hours and minutes and send it to the time selector?