The rich flavor of porcini mushrooms, featured in both the stuffing and the sauce, is the hallmark of this elegant roast that makes a delicious centerpiece on your holiday dinner table.
Note: To make your own porcini powder, place one or two dried porcini in a spice grinder and grind to a powder. Store any unused porcini powder in an airtight container, where it will keep for several months.
For the stuffing:
- 3 dried porcini mushrooms
- 2 tablespoons olive oil
- 1 medium yellow onion, minced
- 1 celery rib, minced
- 2 garlic cloves, minced
- 2 cups coarsely chopped white mushrooms
- 1 teaspoon dried thyme
- 1⁄2 teaspoon dried sage
- 1⁄2 cup water
- 1 teaspoon salt
- 1⁄4 teaspoon freshly ground black pepper
- 11⁄2 cups cooked brown rice
- 3 cups fresh bread cubes, finely chopped
- 1⁄4 cup minced fresh parsley
For the seitan:
- 2 cups vital wheat gluten (wheat gluten flour)
- 1⁄4 cup nutritional yeast
- 1 teaspoon porcini powder (see note above)
- 3⁄4 teaspoon onion powder
- 3⁄4 teaspoon salt
- 1⁄2 teaspoon garlic powder
- 1⁄2 teaspoon sweet paprika
- 11⁄2 cups cold water
- 1⁄4 cup soy sauce
- 2 tablespoons olive oil plus more for rubbing
For the sauce:
- 1 tablespoon olive oil
- 3 tablespoons minced shallot
- 2 cups assorted fresh mushrooms, lightly rinsed, patted dry, and cut into 1⁄4-inch slices
- 1 teaspoon minced fresh thyme leaves, or 1⁄2 teaspoon dried
- 2 cups vegetable broth
- 2 tablespoons soy sauce
- 1 tablespoon minced fresh parsley
- Salt and freshly ground black pepper
- 2 tablespoons cornstarch
- 1⁄4 cup water
- 1⁄2 teaspoon browning liquid
For the stuffing:
Place the dried porcini in a heatproof bowl and cover with boiling water. Set aside for 20 minutes to soften.
In a large skillet, heat the oil over medium heat. Add the onion and celery. Cover and cook until soft, about 10 minutes. Stir in the garlic, mushrooms, thyme, sage, water, salt, and pepper. Cook until the mushrooms release their juices, about 3 minutes. Remove from heat and set aside.
Drain the soaked porcini and finely chop. Stir them into the onion and mushroom mixture and transfer to a large bowl. Add the rice, bread and parsley and mix well, adding a little more water if the stuffing is too dry. Taste and adjust seasonings, if necessary. Refrigerate to cool completely while you make the seitan.
For the seitan:
In a food processor, combine the vital wheat gluten, yeast, porcini powder, onion powder, salt, garlic powder, and paprika. Pulse to blend. Add the water, soy sauce, and oil and process for a minute to form a soft dough. Turn the mixture out onto a lightly floured work surface and stretch it out with lightly floured hands until it is flat and about 1⁄2 inch thick. Place the flattened seitan between two sheets of plastic wrap or parchment paper. Use a rolling pin to flatten it as much as you can (it will be elastic and resistant). Top with a baking sheet weighed down with canned goods and let it rest for 10 minutes. Preheat the oven to 350˚F.
When the stuffing is completely cool, place it in the center of the seitan and use your hands to press the stuffing into a firm log. Roll the seitan up and around the stuffing, using your fingers to seal the ends and the seam. Place the seitan on a large sheet of foil and roll it up, twisting the ends to seal. Place the wrapped seitan in a deep baking pan. Pour hot water into the pan about halfway up the sides of the seitan. Cover the pan tightly with foil and bake for 40 minutes.
Lightly grease a separate large baking pan. Remove the seitan from the water and remove the foil. Place the seitan in the prepared baking pan. Rub a little oil on the top and sides of the seitan and bake until firm and glossy brown, about 20 minutes.
For the sauce:
In a large saucepan, heat the oil over medium heat. Add the shallot and cook until soft, about 5 minutes. Add the mushrooms and cook 2 minutes longer. Add the thyme, broth, soy sauce, parsley, and salt and pepper, to taste. Bring to a boil. In a small bowl, combine the cornstarch and water and mix until blended. Reduce the heat to low, whisk the cornstarch mixture into the sauce, and stir until it thickens, about 3 minutes. Stir in the browning liquid. Taste and adjust seasonings, if necessary. If not using right away, bring to room temperature, then cover and refrigerate for up to 3 days.
Remove the seitan from the oven and set aside for 10 minutes before slicing. Use a serrated knife to cut most of it into 1/2-inch slices, leaving about one-third of it whole. Arrange the seitan on a large platter and pour some of the mushroom sauce on top. Serve hot with the remaining mushroom sauce at the table.
Note: If you’re planning to make this roast ahead of time (up to a day in advance), do not slice it. Instead, let it come to room temperature after baking, then cover and refrigerate until needed. The roast will cut more easily (and in neater slices) when chilled. Once sliced, you can then reassemble the roast and wrap it tightly in foil before reheating in the oven.