Add the shiitake mushrooms to a larger freezer bag or 9 x 13 baking dish.
In a small bowl, add coconut aminos, vinegar, olive oil, sesame oil, paprika, garlic, nutritional yeast, and pepper. Pour over mushrooms.
Cover and refrigerate for at least 8 hours for overnight.
Preheat the oven to 250 degrees. Line two baking sheets with parchment paper.
Remove the mushrooms from the bag or dish, shaking off the excess marinade, and place onto baking sheets. Make sure to spread the mushrooms out evenly.
Bake for one hour. Then, flip the mushrooms and cook for another 50-60 minutes.
Allow the mushrooms to cool completely. Then, store in an airtight container.