Cooking with Oysters

by Joe and Kathy Brandt

Gertrude Monnet of Switzerland happily shows off a basket containing six pounds of oyster mushrooms. Photo by Tjakko Stijve

Gertrude Monnet of Switzerland happily shows off a basket containing six pounds of oyster mushrooms.
Photo by Tjakko Stijve

Oscar Wilde once said “The world is my oyster”. Since oysters (Pleurotus ostreatus) are without a doubt one of the best (and most versatile) mushrooms in the world, that would mean – well, it must mean something. OK: show of hands – who has never had any experience with oyster mushrooms? Hmmmm….. Not many, not many.
How shall we love thee? Let us count the ways! That, of course, would be tricky at best, because we could fill an entire issue (let alone one little column) singing the praises of this splendid species, let alone listing recipes! The flavor appeals to a wide variety of palates; the texture (when found in good condition and properly cooked) is well suited to a great range of dishes, and in many areas, they may be found with enough frequency that a ready supply of them (in season) is generally not problem. In fact, many mainstream supermarkets offer a cultivated variety for sale, and although these are rarely comparable in flavor to the wild counterpart frequently seen in many of our northern states (particularly those that may be found once the weather turns chilly), they are certainly not anything that should be dismissed as being unsuitable for cooking, especially if you have not had the good luck to have located any in the wild. In fact, at a recent NorthEast Mycological Federation (NEMF) foray, we used cultivated oysters as the basis for Oystah Chowdah (recipe follows), which we made for 275 attendees.
As many of you are probably aware, there is often a dramatic difference between the condition of (wild) oysters found during warm weather, and those found from early fall to early (or even mid-) winter. Love those oysters? Rest assured, the bugs do, too – and when it’s warm, the chances of finding insect-free oysters is remote. (Small beetles are easy to deal with, but the little white grubs that bore through the inner flesh are impossible to remove, and will lay a choice-looking mushroom to waste in as little as one day.) Once the weather has become a bit colder (and especially once there has been a frost or two at night), the probability of insect infestation reverses, and a great majority of the oysters you are liable to come across will likely be in pristine condition, provided they have been located within a week or so after they have emerged. As the accompanying article by Greg Marley details, colder-weather oyster caps are generally rounder and brownish in appearance, compared to their flatter, whiter, warm-weather counterparts. The colder the weather, the less chance there will be of insect infestation of any kind, and the taste of winter oysters is stronger and more intense in comparison to the blander summer oysters .
Oysters (brown-capped, on the right) and Late Fall Oysters (green-capped, on the left. Photo by Greg Marley

Oysters (brown-capped, on the right) and late fall oysters (green-capped, on the left.
Photo by Greg Marley

There is also a “Late Fall Oyster” (Panellus serotinus), which is somewhat different in both appearance (yellowish-green cap with yellowish gills) and taste (stronger, and sometimes slightly earthy/bitter) from P. ostreatus. Since cooking methods differ appreciably, we will save a description of the culinary usage of Panellus serotinus for another time.
Although oysters can hold up fairly well if refrigerated, we always recommend that they be processed as soon as possible, because (as we’ve seen on too many occasions) if you happen to have a very slight grub infestation (which can generally be handled by immediately discarding any compromised areas) that is left unattended for a day or so, the grubs will spread like wildfire, refrigerated or not. (And by the way, do not leave oysters sitting out on a counter for any great length of time, because grubs have a tendency to get out and go exploring – ‘nuf said.) Oysters, like most mushrooms, will suck up water like a sponge, so it’s important to try not to immerse them in water while cleaning. Use water only as necessary, and try to avoid exposing the gills to water for any length of time, as these will absorb liquid faster than the “cap” side. If it’s necessary to use water on both sides, we advise employing a gentle “squeezing” technique to drain off excess water prior to slicing, otherwise, you’re going to wind up with so much liquid in your pan once you start cooking them that they might as well be boiled. As with most other mushrooms, a damp cloth is the best way to clean them if possible. A soft brush is always useful, and a knife point may be employed for dislodging stubborn or embedded debris. As a rule of thumb, only the caps will be soft enough for cooking; the stems (and central “body” stalk, if any) are normally too tough to use, and these areas will also be more likely to harbor insects than the caps themselves. Prior to cooking, we recommend that caps be sliced crosswise, and always observe the exposed cut surfaces carefully, as tiny grub tunnels will rarely be apparent from the outside surface of the caps.
Once cooked, oyster mushrooms may be successfully frozen without difficulty, and will keep for quite a long period of time (a year, no problem) before they noticeably begin to lose flavor. (It is always recommended that as much air as possible be removed from the container prior to freezing.) Oysters may also be dehydrated for storage, which frees up space in your freezer (and dehydrated mushrooms will keep almost indefinitely if properly stored), but we find that the best method of preserving the flavor and texture is freezing, if circumstances permit.

Basic Oysters

3 Tbsp olive oil
4 cloves minced garlic
2 onions, chopped
1½ tsp salt
1½ tsp ground cumin
¼ tsp fresh ground pepper
10 cups sliced oyster mushrooms
Tamari/soy sauce (optional)
Heat oil in a large sauté pan, medium heat. Add garlic, stir once. Add onions, cook 5 minutes. Add half of the salt and cumin, then add the mushrooms and mix well. Continue to cook for 20-25 minutes (stir every few minutes to prevent sticking), adding remaining salt and cumin gradually. Here’s the thing: you can be conservative with the initial application of salt and cumin, since you can always add more (and you’ll probably want to, trust us) to taste. (If in doubt, add more salt & cumin.) Add pepper about halfway through cooking. Tamari may be added to taste at almost any time. Add 2 tsp. water if dry. (Should be slightly browned when done.) They may be eaten as is, on pasta or rice, in a wrap with other ingredients, or used in recipes that do not require a great deal of additional cooking time. Once cooked, they will keep just fine in the ‘fridge (tightly covered) for several days, or they may be frozen for use at another time.
If you’ve had the good fortune to find a very large quantity of oyster mushrooms, you can double (or triple) this recipe and bake them. Put all the dry seasonings together, and place the oysters into a very large bowl. Drizzle on the olive oil while tossing until evenly coated. (You may be able to use a bit less oil than the recipe calls for) Add in the garlic & onions and toss to mix. In stages, sprinkle on the dry ingredients, and toss to coat evenly. Transfer to a large baking pan (use an extra pan if needed), cover with foil, and put into a 350° oven for 30 minutes. Remove foil and stir. Replace foil, return to oven for 30 minutes. Remove foil and stir. Return to oven (uncovered) for another 30 minutes. (Yes, that’s a total of 90 minutes cooking time.)

Oystah Chowdah1

2 Tbsp butter substitute: Earth Balance or similar (You can use unsalted butter; but as written, the recipe is designed to be vegan.)
¼ lb oyster mushrooms cut into 1/2 inch pieces
½ cup raw cashews
2 cups vegetable broth, divided
2 cups water
½ cup onion, diced
1½ cups cauliflower, cut into pieces
¼ tsp. minced garlic (or a bit more to taste)
3 bay leaves
½ tsp thyme, dried
¼ tsp white pepper
1 tsp salt (or less, if the veggie broth is salty)
1½ cups diced peeled potatoes (We generally use red potatoes, unpeeled)
¼ tsp natural smoke flavor, optional
¼ tsp fresh ground black pepper
1 Tbsp parsley, minced

1Reprinted courtesy of VegNews Magazine. Recipe by Allison Rivers Samson, owner of, a vegan, organic, artisan bakery and gift shop.

In a skillet, sauté 1 Tbsp. butter substitute (or butter) and oysters (7 minutes), then set aside. (If using pre-cooked mushrooms, skip this step entirely.)
Grind cashews to a fine powder, then add 1 cup broth. Blend until smooth. In a stock pot, over medium high heat, add 1 Tbsp butter substitute, onion, cauliflower & garlic. Sauté 5 minutes, then add bay leaves, thyme, white pepper, remaining broth, water, cashew mixture & salt. Bring to a boil, reduce heat to low, cook 15 minutes. Remove bay leaves. Transfer to a blender, blend completely until smooth. Return to pot, add potatoes, cook over low heat for 40 minutes. Add mushrooms (and the smoke flavor, if using), stir & cook another 5 minutes. Serve hot, garnished with a sprinkle of fresh parsley and a few oyster crackers, if you’ve got ‘em. (Serves 4)

Oyster Stew

4 Tbsp. unsalted butter
¼ cup finely chopped onions
½ cup finely chopped celery
2 Tbsp. finely chopped shallots
1 tsp. minced garlic
½ pound assorted mushrooms (wild, store, combo), cleaned & chopped
½ tsp. fresh thyme leaves, chopped
½ cup dry white wine or sherry
2 cups half & half
1 pound oyster mushrooms, sliced & cooked in 2 Tbsp. olive oil and ½ tsp. ground cumin (drain off & reserve liquid)
2 tsp. fresh lemon juice
Fresh ground white pepper
2 Tbsp. chopped parsley
Finely chopped chives (garnish)
Thin sliced garlic toast
In a large saucepan, melt butter (medium-high heat), add onions, celery & shallots. Cook, stirring, until soft, 3 minutes. Add garlic, cook (stirring) 30 seconds. Add the assorted mushrooms and thyme. Cook until mushrooms give up their liquid, 4-5 minutes. Add wine (or sherry), bring to simmer, stirring until liquid is reduced by half. Add half & half and the reserved oyster liquid, cook until slightly thickened. Add lemon juice and the oyster mushrooms. Cook until oysters start to curl, 2-3 minutes. Stir in parsley, adjust seasonings to taste. Ladle into bowls, garnish with chives and garlic toast. Serve hot.

This article was originally published in the Fall 2009 issue of Mushroom the Journal.