Rotation of an object with some delay..

I've just started working on unity with very little knowledge in scripting..as a learning activity i'm trying to rotate an object to the mouse pointer on click...so far i've got the rotation working but the rotation happens in a single frame and i want to make the object rotate with some delay...need help to figure that out. code so far is Ray ray = (Camera.main.ScreenPointToRay(Input.mousePosition)); Physics.Raycast(ray, out hit); hitpoint = hit.point; direction = hitpoint - this.transform.position; Vector3 relative = transform.InverseTransformDirection(direction); angleRad = Mathf.Atan2(relative.x,relative.z); angleDeg = angleRad * Mathf.Rad2Deg; transform.Rotate(Vector3.up,angleDeg);

I've used manual trigonometric calculations instead of functions like Quaternion.LookRotation just to get my hands dirty with vectors.

~Thanks