While barley is low in gluten, it is not gluten-free. So if you’re having G/F guests (or if you or your household members are G/F), you could do this with quinoa, millet or rice–a wild rice blend would be very nice indeed. On the other hand, barley is not wheat or even one of the close cousins of wheat like kamut, faro, emmer-wheat and the like. So this dish is suitable for those who eschew wheat but tolerate small amounts of gluten just fine.
Don’t fall into the fallacy of getting lots of very tiny mushrooms. Even if they’re on the menu as an appetizer. They shrink when you cook them, and you’ll be frustrated trying to get a 1/2 teaspoon of filling into all those tiny, little apertures. Do consider these as a great vegetarian main dish, especially if you use portobello mushrooms, or very large cremini say. They also make a lovely side dish for omnivore plates.
The volumes given below will fill about 6 dozen appetizer sized mushrooms, or 15-20 portobellos–depending on how big they are and how high you pack the stuffing.
Barley Stuffed Mushrooms
For the barley:
5 oz barley, hulled is special here
12 oz water
1/2 tsp salt
For the mushrooms:
6 dozen good sized fresh button or cremini mushrooms, stemmed (save the stems for another project) and wiped of their dirt
15-20 firm fresh portobellos
salt for sprinkling
For the stuffing:
1 1/2 oz hazelnuts, toasted, rubbed (to remove their skins), and chopped
3 TBSP olive oil, or butter
1 small apple, peeled if you like, cored and chopped quite small
1 shallot, minced
1 small stalk of celery, leafy tops included, minced
1/2 tsp powdered fennel
1/2 tsp dried thyme, or a TBSP of fresh
1/2 tsp rubbed sage
1/4 grated nutmeg
1/2 tsp black pepper
1/4 cup minced (Italian flat leaf) parsley, volume after mincing
The cooked barley from above
[optional] 3 oz blue cheese or vegan blue cheese, crumbled
Put the barley, water and 1/2 tsp salt in a small saucepan. Cover and bring to a boil. Reduce to a simmer and cook about 50 minutes. You want the barley VERY done. If you chose hulled barley, cook about 10 minutes longer. Leave the barley sitting off the heat in the covered saucepan about 15 minutes. Then drain it thoroughly, about ten minutes in a colander or strainer.
Preheat your oven to 350°F. Set your mushrooms, aperture side up on an edged baking sheet. Sprinkle them lightly with salt. Cook for 10-15 minutes, they should have liquid sitting in their ‘wells’ when they’re ready. Take them from the oven and turn them over. Set them back in the oven for another ten minutes. This drying process prevents them becoming soggy when filled and finished.
In a heavy bottomed frying pan, get your fat hot over medium heat. Add the apple and cook for several minutes. Then add the shallot and celery. Let this cook for several minutes more, stirring occasionally. You want the apple to begin to caramelize, and the celery to soften, but you don’t want the shallot to caramelize–since it only becomes bitter instead of sweet like its cousin the onion.
Now and the fennel, thyme, sage, nutmeg and black pepper. Stir these well in and cook for another minute or two. Remove from the heat and stir in the chopped hazelnuts, the parsley, the barley and the blue cheese/cheeze (if using). Check the seasoning on the stuffing and correct if necessary.
Hold the mushrooms over the bowl of stuffing as you stuff them, that way the ‘crumbs’ will fall back into the mixture instead of gumming up your rimmed baking sheet. Pack them fairly full and very tightly. Set them on your baking sheet as they’re filled. The mushrooms can be very close together, as they shrink while cooking.
Bake at 375°F for 15 to 20 minutes, for the little ones and 20-25 minutes for the big ones. Serve immediately.
You can make the stuffing several days ahead of when you hope to serve it. You can prep the mushrooms up to a day and a half ahead. Do refrigerate these components in tightly lidded containers if you’re not going to finish them at once.