I’m personally looking for a better implementation than the one I have but here are my 2 cents on the topic.
As far as I know this is a kinda, I have not been able to make Unity recognize a class method as a property, these seem to be (and I may be completely wrong here) reserved for fields only.
My solution was to create a custom attribute called ButtonUtilityAttribute that is then attached to a field (I normally make them be bytes) and that uses reflection for when the button is hit to call the function.
Personally I would like to be able to move the attribute to the method rather than having to create a dummy variable in the class.
Anyhow hope this helps for the time being. The drawer implementation is rather straightforward, just use reflection on the object it is running for to find the method call that is specified in the attribute constructor and set the label as the second parameter from the attribute.