Preheat your oven to 400°F (200°C). Cut the acorn squashes in half and scoop out the seeds. Brush with olive oil, season with salt and pepper, cut-side down on a parchment-lined baking sheet, and roast for 30–35 minutes.

In a skillet, heat olive oil over medium heat. Add the chopped yellow onion and sauté for 3–4 minutes until translucent and fragrant. Toss in the minced garlic and cook for an additional minute.

Add diced red and yellow bell peppers to the skillet, cooking for 3–4 minutes until softened. Stir in sun-dried tomatoes, cooked quinoa, dried thyme, oregano, and salt and pepper; let cook for 5 minutes.

Flip the roasted acorn squash halves over. Spoon the quinoa and vegetable mixture into each half, pressing down gently to pack it tightly.

Sprinkle the stuffed squash with mozzarella or Gruyère cheese and grated Parmesan cheese. Return to the oven and bake for 10–15 minutes until cheese is melted and bubbly.

Remove from the oven, cool slightly, and garnish with freshly chopped parsley. Serve warm.