Combine mushrooms and beef with fish sauce, rice wine vinegar and sesame oil in a bowl and mix with a light hand. Rest for 10 mins.

Wet a kitchen towel and spread on the counter (keep sprinkling water on the towel as needed), and place a rice paper roll on it gently pressing for a few seconds to soften it. Gently lift the roll, place on a chopping board and spoon a little mushroom filling topped with a few of the greens an inch above the edge, fold in both the left and right sides and the bottom, then roll to resemble a spring roll (see pictures). Keep the rolls covered to prevent them from drying out as you make the rest of the rolls.