Preheat your oven to 375°F (190 °C). Wash your mushrooms well by rubbing off any dirt and rinsing them under water. Don't soak or submerge your mushrooms. Cut off the brown spot at the end of the stems and discard.
Use a spoon to scoop out the stems and gills of the mushrooms, and save what you scrape out. Then, chop the stems and gills into very small pieces. (Chop up any broken or ugly mushrooms too until you have 1 cup of finely chopped mushroom pieces.)
Place the hollowed-out mushrooms on a cookie sheet lined with parchment paper (or oiled). Spray both sides of the mushrooms with a light coating of spray oil.
Make the mushroom filling
Saute the chopped mushrooms in 1 tablespoon of vegan butter (or oil) with 1/8 teaspoon of salt over medium-low heat for about 5 minutes, until they are soft and release their juices.
Add 1 tablespoon Bragg's Liquid Aminos, 1 teaspoon Italian herbs, 1/4 teaspoon red pepper flakes, 1/4 teaspoon fennel seeds, and 1/2 cup water; stir well until it comes to a boil, then turn off the heat.
Sprinkle in the 1/3 cup of TVP, stir well, and cover for 5 minutes to let it absorb some of the liquid.
Add 1/3 cup breadcrumbs, 1/2 cup vegan cheese, and 3 tablespoons finely chopped parsley. Stir, then cover again for 5 more minutes to let the cheese melt a little.
Stuff and bake the mushrooms
Stuff the mushrooms with the filling mixture so that it's heaping up in the center. (You can top them with additional cheese if you would like.)
Bake the stuffed mushrooms at 375°F (190 °C) for 20 minutes, until golden on top. Serve hot.
Notes
Choose mushrooms that are as firm and fresh as possible. Don't use mushrooms that have bruising or are starting to get soft.
For gluten-free, vegan stuffed mushrooms, or just to make them "meatier," swap out the breadcrumbs for an equal amount of TVP.
For a full list of substitutions, see the ingredients and substitutions section of the post.
See the post for storage and reheating instructions.