Custom Mob - Guaranteed Drop

Hello guys, I'm kinda confuse here, I have made a Custom Mob, and I want it to drop always certain item in a quantity of 1

So I have this on the code

    @Override
    protected Item getDropItem()
    {

    	return ModItems.apple_ext;
    	
    }

But I think, this code actually will drop this item, at a chance, right?

If so, how should I make it.