Place leaves in a Multipurpose Steamer; cover with lid (it’s ok if not snug!). Microwave on high, at 1 min intervals until wilted, about 3 min. Spread leaves out on the counter to cool.
Meanwhile, finely chop mushrooms. You’ll need about 2 cups. Using a box grater, coarsely grate carrots. In a large bowl, combine pork, mushrooms, carrots, seasoning, cornstarch, and soy sauce.
To assemble, cut out and discard thick stem end from the bottom of each leaf; this will make them easier to roll. Divide filling between leaves. Fold 1 end and both sides over filling; roll up. Tuck rolls, seam-side down in Multipurpose Steamer; it’s OK if they overlap.
Cover; microwave on high until rolls are firm, about 7 min. Using tongs, remove to plates; discard liquid. Serve warm.