Hi @guimenez
Assuming we stick with UTC for a moment, try:
if(
or(
equals(formatDateTime(items('Apply_to_each')['Start'],'hh'),'00'),
equals(formatDateTime(items('Apply_to_each')['Start'],'hh'),'01')
),
formatDateTime(items('Apply_to_each')['Start'],'dd-MM-yyyy'),
formatDateTime(items('Apply_to_each')['Start'],'dd-MM-yyyy hh:mm')
)