Wash the sweet potatoes thoroughly, then pierce them several times with a fork. Place them on a baking sheet lined with parchment paper.
Bake the sweet potatoes in the preheated oven for 45 minutes, or until they are tender when pierced with a knife.
While the sweet potatoes are baking, prepare the Mediterranean filling. In a large bowl, combine the cooked quinoa, halved cherry tomatoes, diced cucumber, crumbled feta cheese, sliced olives, red onion, and chopped parsley.
In a small bowl, whisk together the olive oil, lemon juice, oregano, garlic powder, salt, and pepper. Pour this dressing over the quinoa mixture and toss gently to combine.
Once the sweet potatoes are done, remove them from the oven and let them cool for a few minutes. Slice each sweet potato in half lengthwise and gently fluff the inside with a fork.
Spoon the Mediterranean filling generously into each sweet potato half.
Return the stuffed sweet potatoes to the oven and bake for an additional 10 minutes to warm the filling through.
Remove from the oven and serve warm, drizzled with any extra dressing, if desired.
Notes
Feel free to add more vegetables or adjust the seasoning to your taste.