I know nothing of mushroom ID's, except maybe the woodear fungus that grows logs. I saw this HUGE mushroom/fungus growing next to a big round on the woodyard. I've heard of hen of the woods or chicken of the woods down here in the south... Here is a picture...reference for size, that is a 44" round of post oak it is growing next to...
Looking at it, reminds me of cauliflower. So I looked it up. Could be: cauliflower mushroom - Google Search
When the men on the chessboard Get up and tell you where to go And you've just had some kind of mushroom And your mind is moving low Go ask Alice I think she'll know
My guess is chicken of the woods. They usually grow in or around dead oak stumps. I get them pretty good in my area along with a few others I haven't a clue of. Suppose to be a real treat but I just don't know when to pick em, they turn firm quick and start to turn black.