Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.

Clean the portobello mushrooms with a damp cloth, remove stems, and scrape out gills. Brush with olive oil and season with salt and pepper.

In a saucepan, bring vegetable broth to a boil, add quinoa, stir, cover, and simmer for about 15 minutes.

In a skillet, warm olive oil over medium heat, add diced butternut squash, and sauté for 8-10 minutes. Add garlic and thyme, cooking for an additional minute.

In a mixing bowl, combine cooked quinoa, sautéed squash, cranberries, and walnuts. Stir well.

Stuff each mushroom cap with the filling and top with grated parmesan cheese.

Bake the mushrooms on the prepared baking sheet for 20-25 minutes until tender and cheese is melted.

Allow to cool for a few minutes before serving.