If I were to make this tonight (Tuesday), would it still be in great shape for Thanksgiving? Or should I wait and make it on Wednesday?

I think that you can make the mushrooms tonight and store them in the fridge until Thursday. On Thursday, I'd bring them to room temperature, add the splash of vinegar, check the seasonings and add the parsley. By not finishing the dish until the last minute, you'll give the salad fresh flavor.

Just read that recipe. YUM! You can definitely make it tonight, just wait to add the parsley until Thursday morning. That will keep the flavors fresh and bright.