Help with Quatrenion.slerp

Unity Engine
1

All i want is to slerp form my gameObject’s starting rotation to a rotation that equals its starting rotation +45 degrees around the Z axis. its just confusing the hell out of me

2 
Vector3 targetRotation;

void Start ()
{
    targetRotation= transform.eulerAngles + new Vector3 (0, 45, 0); // Or whatever
}

void Update ()
{
    transform.eulerAngles = Vector3.slerp (transform.eulerAngles, targetRotation, 0.1f);
}