Mouse ear mushrooms, "het huu nuu"
Fry in oil before adding to bamboo soup or chicken curry. Sliced, they maybe used in fresh Vietnamese spring rolls. With pork or chicken, they make a stir fry.

The spoon is included in the picture to give readers a sense of scale.
From the recent book "Food from Northern Laos"
http://www.foodfromnorthernlaos.com