How to Make It
Bring 6 quarts of the water to a boil in a large stockpot over high. Trim 1/4 inch away from each mushroom stem. Quarter mushrooms. Add mushrooms to water; cook 45 seconds. Drain and transfer mushrooms to a large bowl.
Combine vinegar, miso, salt, red pepper, paprika, and remaining 1 1/2 cups water in a medium saucepan; bring to a boil over high.
Drain mushrooms again. Add parsley, rosemary, garlic, and thyme to mushrooms; toss to combine.
Add boiling vinegar mixture to mushrooms in bowl. Let stand at room temperature 5 minutes. Carefully ladle mushroom mixture evenly into 6 (1-pint) canning jars. Wipe rims. Cover at once with lids; screw on bands. Cool jars to room temperature. Refrigerate 2 days before serving. Pickled mushrooms will keep up to 1 week in refrigerator.
This recipe requires 2 days for chilling.