Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper. Gently clean the portobello mushrooms with a damp paper towel, removing any dirt. Remove the stems and gills, then brush both sides with olive oil. Season with salt and pepper.

In a medium saucepan, combine 1 cup of quinoa with 2 cups of vegetable broth or water. Bring to a boil, then reduce heat to low, cover, and simmer for about 15 minutes until fluffy. Fluff with a fork and let cool slightly.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add 1 cup of diced butternut squash and sauté for 8-10 minutes until tender and caramelized. Stir in 2 minced garlic cloves and fresh thyme, cooking for an additional 1-2 minutes. Season with salt and pepper.

In a mixing bowl, combine the cooked quinoa, sautéed butternut squash mixture, ½ cup of dried cranberries, and ½ cup of chopped walnuts. Mix well, adjusting seasoning if necessary.

Fill each portobello mushroom cap with the quinoa mixture, pressing down slightly. Sprinkle about ½ cup of grated Parmesan cheese over the tops.

Place the stuffed mushrooms on the prepared baking sheet and bake for 20-25 minutes until tender and cheese is melted and golden brown.

Let the mushrooms cool for a few minutes on the baking sheet before serving warm.