A couple of days ago, I came across this like fancy trick to make mushrooms look pretty, and so I learnt that it’s called fluting. I think brown cap mushrooms are best for this so you see the design better with the difference in colours.
With a small sharp knife in hand, press the cap of the mushroom gently but surely against the knife. Note that the mushroom is cut by being pressed towards the knife; while the knife stays rather still throughout. Of course, this is done before the mushroom is cooked.
I think before this, mushrooms never looked more presentable.
Try it today!