Creating these amazing Stuffed Portobello Mushrooms is straightforward. Follow these steps for a perfect result:

1. Preheat the Oven: Start by preheating your oven to 375°F (190°C).
2. Clean the Mushrooms: Remove the stems from the Portobello mushrooms and gently scrape out the gills using a spoon.
3. Prepare the Filling: In a mixing bowl, combine the cooked quinoa or rice, shredded mozzarella cheese, cooked spinach, sun-dried tomatoes, grated Parmesan, minced garlic, chopped basil, salt, and pepper. Stir well until all ingredients are evenly distributed.
4. Stuff the Mushrooms: Place the cleaned mushrooms on a baking sheet. Generously fill each mushroom cap with the prepared filling.
5. Drizzle with Olive Oil: Lightly drizzle olive oil over the top of the stuffed mushrooms to enhance flavor and promote browning.
6. Bake: Place the baking sheet in the preheated oven and bake for about 25-30 minutes, or until the mushrooms are tender and the cheese is bubbly.
7. Add a Final Touch: Optional – drizzle with balsamic glaze for an added layer of flavor right before serving.
8. Serve: Once done, remove the mushrooms from the oven and let them cool for a few minutes before serving.

Following these steps will help you create deliciously stuffed mushrooms that impress both visually and gastronomically.