Create new sensor from part of another sensors attribute

Configuration
1

Trying to figure out how to create a new sensor using only a part of an attribute from another sensor.

I am able to create the new sensor and have it pull the attribute I want but I am struggling to workout how to have it only pull the part that I want.

This is the attribute data that my sensor has but I only want the time and not the date

start_time: 2022-01-13 14:15:00

Here what I have for my sensor so far

tottenham_event_day_start:
friendly_name: "tottenham event start"
value_template: "{{ state_attr('calendar.tottenham_hotspur_fc', 'start_time') }}"

There is probably a way better way of doing this that all you wizards use

Thanks

2 
value_template: "{{ state_attr('calendar.tottenham_hotspur_fc', 'start_time').split(' ')[2] }}"