I love marinated mushrooms. Period.
It's just hard to find a nice, clean, easy, quick recipe. Look no further. Using the Chopped Cookbook as a base, I modified their recipe for Quick Pickled Baby Cremini into a slightly heartier and elegant recipe.
The basic recipe goes like this:
1 pound mushrooms
2/3 cup each vinegar and water
1 tablespoon each salt and sugar
Combine all in a pot. Bring to a simmer, and simmer for 4 minutes. Take off the heat, add 1/2 cup thinly sliced red onion. Let sit for 45 minutes. Serve warm or refrigerate.
I followed the base recipe but added a sprig of thyme, a sprig of tarragon, dill, red peppercorn, California red pepper flakes, coriander, parsley, cilantro, dehydrated garlic (from Penzey's), 2 full heads of garlic cloves, and varied the vinegar between a 20 year homemade red wine vinegar, a cider vinegar, and white wine vinegar to equal the 2/3 cup. I used 3/4 shiitake mushrooms and 1/4 white button mushrooms since that's what I had on hand. Just be careful with shiitake mushrooms as the dried and rehydrated ones will suck up a LOT of vinegar solution and have to be used sparingly.
This would work with any vinegar and any combination of mushrooms. They fit perfectly in a 1 quart mason jar pressing down to ensure all are submerged. It won't seem like enough liquid while cooking but when you put them in a jar it will be perfect. Just keep stirring while simmering to ensure even cooking.
My fiance loves the mushrooms chilled, however I let them cool in the 1 quart mason jar at room temperature for the 45 minutes before putting them in the fridge.
The other thing I love? No oil, so fat free.