Slice bread into 1 inch cubes and lay on a baking sheet to dry out for at least 24 hours. If you are short on time, you can dry out the bread in the oven. Preheat oven to 300 degrees F and toast bread for 25-35 minutes, until dried out. I actually did both since my bread was super fresh. I let it sit out for 24 hours then baked it for 25 minutes to dry it out more. I don’t like super soggy bread in stuffing.
Make the flax egg in a small bowl by combining the ground flaxseed and water. Stir until combined. Set aside.
Preheat oven to 350 degrees F. Grease a 9×13 baking dish and set aside.
In a large pot, over medium high heat, add the oil and butter. Wait until butter is melted, then add the onion, garlic, celery, and carrots. Sauté for 5 minutes. Next add the mushrooms and sauté for 6-8 minutes, or until most of the liquid is cooked off. Add the sage, thyme, rosemary, salt, and pepper. Stir and cook for 1 minute.
Turn heat off and add the nutritional yeast and miso. Stir until combined and add 1 cup of broth. Stir and make sure the miso gets all dissolved into the broth.
Add bread to a very large bowl, the biggest bowl you have. Then add the flax egg and the vegetable broth mixture and stir until everything is combined. Drizzle the last 1/2 cup of broth, you might need less depending on how wet/dry your bread is. You don’t want it soaking wet, just all the bread moistened.
Place stuffing in the prepared baking dish and lightly cover with foil. Bake for 35 minutes. Then remove foil, place back in the oven, and turn up the heat to 425 degrees F. Bake for another 15-20 minutes until golden brown and crisp on top. Cool for 10 minutes, then enjoy!