Step 1: Roast the Sweet Potatoes

1. Preheat the Oven: Set your oven to 400°F (200°C).
2. Prepare the Sweet Potatoes: Wash the sweet potatoes thoroughly and pierce them several times with a fork to allow steam to escape.
3. Roast: Place them on a lined baking sheet and bake for 45-60 minutes, or until fork-tender.

Step 2: Sauté the Filling

1. Heat Olive Oil: In a large skillet, heat 2 tablespoons of olive oil over medium heat.
2. Sauté Onion & Mushrooms: Add the diced onion and cook for 3-4 minutes until translucent. Stir in the sliced mushrooms and cook for another 5 minutes, until soft.
3. Add Spinach: Stir in the chopped spinach and cook until wilted.
4. Season & Add Feta: Season with garlic powder, salt, and pepper. Remove from heat and stir in the crumbled feta cheese.

Step 3: Stuff & Serve

1. Prepare Sweet Potatoes for Stuffing: Once roasted, allow the sweet potatoes to cool slightly. Cut them in half lengthwise and scoop out a small portion of the flesh to make room for the filling.
2. Stuff the Sweet Potatoes: Spoon the spinach, mushroom, and feta mixture into each sweet potato half.
3. Garnish & Serve: Sprinkle with fresh parsley and serve warm.