I’ve never seen that one, and we’ve had a variety of mushrooms here.
I am not surprised you answered first. We are in the west Michigan woods and have many kinds of mushrooms. I know them pretty well after 35+ years here. Forgot to mention that when fully open caps are close to 4” in diameter. Looked through our 2 mushroom books and went to google images searching under white mushrooms. I was stumped so I turned here.