Slowly rotate while using Quaternion.FromToRotation

In my 2d game I am seemingly forced to use FromToRotation to keep things rotating on the correct plane, problem is is that FromToRotation jumps immediately from current to end and I want to slowly rotate.

I have:

Enemy who tracks the player and rotates to face him.

What are my options for rotating the enemy slowly to face the player while using Quaternion.FromToRotation? I’ve tried Lerp but I couldn’t get it work. If any more details are needed I’ll be glad to add.