How to make something rotate faster and faster

I have an orb in my game and it rotates 25 degrees per second from a script but I want to make so it can attack and I want it to go faster and faster after every second so it “charges” itself how would you approach that?

Save the rotational speed to a variable, then add a certain amount to that variable every second. Apply rotation to object.

public float originalRotationSpeed = 25f;
public float rotationIncrement = 1f;
public bool incrementRotation = false;
public float currentRotationSpeed;

public void Start()
{
	ResetRotation();
}

public void ResetRotation()
{
	currentRotationSpeed = originalRotationSpeed;
}

public void Update()
{
    float delta = Time.deltaTime;
	transform.Rotate(0, currentRotationSpeed * delta, 0);
	
	if(incrementRotation)
	{
		currentRotationSpeed += rotationIncrement * delta;
	}
}