- Remove the stems from the mushrooms and chop the stems into bite-size pieces. Set the stems and caps aside separately.
- Preheat the oven to 400°F . Heat the oil in a large oven-safe pot or Dutch oven over medium heat. Add the onion and shallots and sauté for about 5 minutes, until softened. Add the flour and cook, stirring, until the flour is not visible, 1 to 2 minutes.
- Add the wine, liquid aminos, Worcestershire sauce, parsley, salt, pepper, and paprika and cook, stirring, for 2 to 3 minutes, until the mixture has thickened. Add the broth and stir in the nutritional yeast.
- Add the chopped mushroom stems, carrots, potatoes, and brussels sprouts and bring to a boil. Reduce the heat to a simmer and cook for about 5 minutes.
- Remove from the heat. Arrange the portobello mushroom caps in the center of the pan, with vegetables surrounding and under them, and spoon sauce over the tops until well covered. Top with the thyme and rosemary sprigs.
- Cover the pot and place it in the oven. Roast for 15 minutes, then remove the lid and roast for another 5 minutes, uncovered. The mushrooms and vegetables should all be very tender. Remove from the oven.
- Remove from the heat. Arrange the portobello mushroom caps in the center of the pan, with vegetables surrounding and under them, and spoon sauce over the tops until well covered. Top with the thyme and rosemary sprigs.
- You can serve straight from the pot, or arrange the portobello caps in the center of a platter surrounded by the vegetables and garnished with the herbs, and spoon the sauce over the top.
- Leftovers will keep in an airtight container in the fridge for 2 to 3 days.