Here's an interesting question from Beth, who is looking forw ways to use the broth left over after reconstituting dried mushrooms.
I started using more dried mushrooms recently - shitake, porcini, and straw to be exact. The last few times, I saved the liquid used to reconstitute them. Afterwards, I simmered the liquid to concentrate it — reducing the volume by about 1/2-2/3. That's as far as my planning for mushroom stock went.I have no idea how to use it other than to replace normal vegetable stock when making soup. Given the stronger flavor of porcini stock over simple vegetable stock, do you have any other suggestions? Googling this question usually results in tips on how to MAKE mushroom stock, not use it.
Beth, this is actually a great problem to have! You can use that liquid in so many ways. To start off, what are you using the reconstituted dried mushrooms for? If it's a soup, pasta, or sauce, you can probably throw the liquid in too. Just replace part of the liquid the recipe calls for with the mushroom broth.
You can reduce it, as you've been doing, and simmer it with some herbs and spices and use it as a sauce for pasta or rice. Or just substitute some of the water you'd use to cook rice for the mushroom liquid. Really, any place you use water or broth you could substitute the mushroom broth. You could toss vegetables in it, or use it to moisten a bread salad.
One tip: Often the liquid left from soaking mushrooms has dirt and grit in it. Get rid of this by sieving the broth through a paper coffee filter.
Here are a few recipes from The Kitchn that either call for mushroom broth or could have it substituted in.
• Recipe: Mushroom Soup
• Recipe: Quinoa and Mushroom Stuffed Zucchini
• Recipe: Rich No-Cream Wild Mushroom Pasta Sauce
• Recipe: Pumpernickel, Watercress and Mushroom Bread Salad
Any more ideas for Beth?
(Image: Cooking Light)
How to Make Fresh Pasta Dough in the Food Processor
How to Make Fresh Pasta Dough in the Food Processor
Good Food to Share 
The Big Book of Small, Cool Spaces 
Apartment Therapy Presents 
The Eight-Step Home Cure 
Floral Drink Dispen...
Small Cool Lessons: Discovering Small Space Design Ideas That Really Work
Marisa and Peter's Playfully Eclectic Home
Uh, yeah... this freakin' awesome Portobello French Dip!!!
http://www.weheartfood.com/2009/02/attention-shroom-lovers-eat-this-french-dip-a-la-cafe-flora.html
An old comfort food in my family is sausage and wild rice casserole -- the best, most flavor rich I've ever made was when I cooked the rice in mushroom stock. Mmmm.
Oh - also have used it to make dressing (or stuffing -- depending on where you grew up) instead of chicken stock. Really delicious.
I add mine to risotto, soup, bread stuffing, quinoa/couscous, bean dishes, and add a few Asian-inspired flavors (sesame oil, chili paste) in order to make a dressing for noodles or a dip for potstickers or spring rolls.
Risotto--yum.
I use mushroom stock to make a mushroom stroganoff using large chunks of portobello mushroom slices.
I add a little bit of flour to about 1 cup of stock (whisked in a separate bowl) and some butter to make a roux, and then pour the roux back into the skillet to thicken the stroganoff sauce.
Those portobello french dips sound amazing.
Use it in gravy. I would also use it as a base for broth for wonton noodle soup.
Ditto on the gravy and risotto, not to mention it's a great veggie substitute for chicken stock in almost any application. It's great for pasta sauce, instead of adding just pasta water, add a few tablespoons of the mushroom stock for added flavor.
Thanks for all the great suggestions! I was unsure whether people found it too strong to use as a substitute for regular vegetable stock. Sounds like that's generally not a problem (if you like mushroomy flavor of course). Thanks for mentioning the coffee filter tip.
I forgot to add that I filled ice cube trays with the concentrated broth and have been adding the cubes sparingly to a couple of pasta sauces and soups. Thanks again!
Beth, I use mushroom stock in my Roasted Mushroom Risotto.
For the non vegetarians out there - and this is just a thought not something I've tried - I'd think a small amount of mushroom stock could add an interesting earthy flavor to a beef stew.
i would love this problem! so many uses! risotto or just cooking rice...
use in place of chicken stock in many recipes (that you have mushrooms or dont mind the flavor)
i would love to have some to do one of my many pork chop preps:
take some thick (preferably brined) pork chops and sear them. once seared remove from pan and add mushrooms and onions. once browned deglaze with some white wine, reduce by half and add your mushroom stock. put chops back in and simmer until done (145!!) take out chops and reduce liquid or make into gravy. serve deliciousness!