Maybe we should more properly call this dressing: Whether you actually use this to stuff a turkey, or bake it outside of the turkey in a casserole or baking dish, it's delicious. It's also extremely forgiving -- use more or less of just about anything in it (onions, celery, chestnuts, mushrooms, herbs, bread. butter, broth), or change up the mushrooms (you can use a mix of dried mushrooms) and it'll still be wonderful. For the chestnuts, you can either roast and peel fresh chestnuts or use pre-cooked and peeled chestnuts that come in a jar.
You can make this entirely ahead, and store it (covered) up to a day in the fridge. Set it in to bake an hour before you want to serve it.
1 - 2 ounces dried porcini mushrooms
1 stick butter
1 medium onion, diced
12 ounces celery (about 6 medium stalks or 1 heart), diced
2 tablespoons chopped sage
4 tablespoons chopped (not too fine) parsley
1 - 3 tablespoons chopped celery leaves (use whatever you have from the celery you diced)
2 tablespoons chopped thyme
8 ounces roasted and peeled or pre-cooked chestnuts, roughly chopped
8 cups dried country French or Italian bread
4 cups chicken broth (from a box or a can is fine)
Salt and freshly ground pepper to taste
1 egg, lightly beaten
1. Reconstitute the dried mushrooms: Place the porcini in a heatproof bowl and pour boiling water over them to cover. Let soak 20 minutes, then -- reserving the liquid -- strain out the mushrooms and set them aside.
2. Melt the butter in a very large pot (I usually use a stockpot or a large Dutch oven) over medium-low heat. Add the onion and celery, and cook until the onions are soft and translucent, about 5 or 6 minutes. Stir in the sage, parsley, celery leaves and thyme, and cook a minute or so, then add the mushrooms and chestnuts. Cook and stir for 2 or 3 minutes.
3. Remove from heat, add the bread and use two wooden spoons to toss it all together. Add the reserved mushroom liquid, the chicken broth and generous grindings of black pepper and toss well to combine. Taste and adjust seasoning, then add the egg and toss well to combine. You can prepare the recipe up to this point, and store it, covered, in the fridge until ready to bake.
4. Heat the oven to 375 degrees. Transfer the stuffing to a large casserole or souffle dish, cover tightly with foil and bake 45 minutes.