Creating Vegan Stuffed Mushrooms is a breeze with these simple steps:

1. Preheat Oven: Preheat your oven to 375°F (190°C).
2. Prepare Mushrooms: Clean the portobello mushrooms and remove the stems. Set the caps aside.
3. Sauté Vegetables: In a skillet, heat olive oil over medium heat. Add diced onion, bell pepper, and minced garlic. Sauté for about 5 minutes until softened.
4. Add Spinach: Stir in the chopped spinach and cook until wilted.
5. Mix Filling: In a bowl, combine the cooked quinoa, sautéed vegetables, dried oregano, smoked paprika, salt, pepper, and nutritional yeast (if using). Mix well.
6. Stuff Mushrooms: Fill each mushroom cap generously with the quinoa mixture.
7. Bake: Place the stuffed mushrooms on a baking sheet and bake for 20-25 minutes, until the mushrooms are tender.
8. Garnish: Remove from the oven and sprinkle with fresh parsley before serving.

These straightforward instructions will guide you to create a delightful dish that everyone will enjoy!