source: Clay T. Martin
Like all duxcels this has a variety of uses. I created this particular mushroom blend to make Mushroom Straws.

1.75 | cups | Black Trumpets, dried |
20 | ounces | Button Mushrooms |
5 | mediums | Shitake Mushrooms, dried |
1 | teaspoon | Black Pepper |
6 | tablespoons | Butter |
0.75 | cup | Chicken Stock |
3 | tablespoons | Flour |
4 | larges | Garlic cloves |
3 | tablespoons | Olive oil |
1 | large | Red Onion |
2 | teaspoons | Salt |

Place your dried mushrooms in enough boiling water to cover. I use a large Pyrex measuring cup, then place a custard dish on top of the mushrooms to weight them down.
When the mushrooms have re-hydrated, strain and reserve the liquid.
Chop all the mushrooms very very fine. The same goes for the onion and garlic.
add half stick of butter and 3 tbs oil to a big fry pan warmed on medium. When the butter melts and the the bubbling subsides, add the onions and saute until the onions are clear.
Add the mushrooms and garlic, stir well. Bring the heat up to med high, and stir regularly. If the pan looks dry add more butter. After a few minutes add the salt. The salt will bring the liquids out of the mushrooms, let them simmer and watch closely, lower the heat as the pan gets drier..
When the mushroom juice is almost completely evaporated, add black pepper and wine. Simmer, on medium high and stir regularly. as the wine goes, turn down the heat. When the wine is almost gone, dust with flour and fry on medium for a minute or two. The pan should get very dry looking. Add the re-hydrating liquid and enough stock to make it 2.5 cups. Return the pan to medium high and stir regularly. As the pan drys, reduce the heat and watch closely. You can burn it easily. Taste for salt and pepper near the end and adjust if you need. You want to reduce this until the only "wetness" in the pan is a coating of oil.

You can make this with almost any mushrooms. Note that fragile mushrooms like black trumpets need to be paired with fleshier ones or they can be damaged. With fleshier chanterelles they can be done on their own.
You can make this up and freeze it, then make more and add it to the same bag (not hot!).
If you need a lot at once, and don't have a large pan you can make up smaller batches and then make a final batch and when the deglazing liquid is half gone add the frozen stuff to the top and let it sit, soon it will defrost and can be mixed in as the Duxcel completes.
Duxcel is a workhorse for the mushroom lover as it allows you to put together smaller finds of mushrooms over time, and it freezes really well. Duxcel can also be used to kick up soups and sauces, stuff under the skin of chicken, mix in with vegetables spread on steak, … well there's no limit!