How do I make an object rotate towards to another object with rotation speed?

I want an enemy chasing the player but I wouldn’t want the enemy to be able to look at me instantaneously.

This is my code for the rotation:

    Vector3 dir = player.transform.position - this.transform.position;
    float angle = Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg;
    transform.rotation = Quaternion.AngleAxis(angle - 90.0f, Vector3.forward);

*edit: Changed added -90.0f at the last line because the sprite was facing the target sidewards.

Try this Unity - Scripting API: Quaternion.Lerp

Try using Time.deltaTime