How do you make a gameobject rotate slowly to the direction of the mouseclick

I'm trying to make it so that when i click anywhere on the screen, the gameobject would gradually rotate to the direction that the mouseclick was in and then immediately stop. The code that i have does actually make it so that the gameobject points to the position of the mouseclick, but that isn't exactly what i want. Any pointers?

 public float speed = 1.5f;
     private Vector3 target;
     Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
     RaycastHit hit = new RaycastHit();
     public Camera currentCamera;
     private Vector3 myPosition;
    
 
     // Use this for initialization
     void Start()
     {
         target = transform.position;
     }
 
     // Update is called once per frame
     void Update()
     {
         if (Input.GetMouseButtonDown(0))
         {
 
             myPosition = transform.position;
             Debug.Log(myPosition);
             Debug.Log("The GameObject has started to MOVE");
             // Rotation
             Vector3 mousePos = Input.mousePosition;
             mousePos.z = 5.23f;
 
             Vector3 objectPos = Camera.main.WorldToScreenPoint(transform.position);
             mousePos.x = mousePos.x - objectPos.x;
             mousePos.y = mousePos.y - objectPos.y;
 
             float angle = Mathf.Atan2(mousePos.y, mousePos.x) * Mathf.Rad2Deg;
             transform.rotation = Quaternion.Euler(new Vector3(0,0,angle));
             target = Camera.main.ScreenToWorldPoint(Input.mousePosition);
             target.z = transform.position.z;
                 target = Camera.main.ScreenToWorldPoint(Input.mousePosition);
                 target.z = transform.position.z;
             }
         //movement
             transform.position = Vector3.MoveTowards(transform.position, target, speed * Time.deltaTime);
 
         }
     }