Creating delicious baked Vidalia onions is a simple process. Follow these steps for a flawless dish:

1. Preheat your oven to 375°F (190°C).
2. Peel the Vidalia onions and trim the tops and bottoms, ensuring they can stand upright.
3. Using a sharp knife, cut a shallow crosshatch pattern into the top of each onion.
4. Drizzle the olive oil evenly over the onions, ensuring they are well-coated.
5. Sprinkle salt, black pepper, garlic powder, and thyme (if using) over the onions, massaging the seasonings in gently.
6. Place the onions in a baking dish, standing upright.
7. Cover the dish with aluminum foil to trap moisture while baking.
8. Bake in the preheated oven for 30 minutes.
9. After 30 minutes, remove the foil and bake for an additional 15-20 minutes, or until the onions are tender and caramelized on top.
10. Once cooked, remove the onions from the oven and let them cool slightly before serving.
11. Garnish with fresh parsley for a pop of color, if desired.

These steps will guide you in creating baked Vidalia onions that are incredibly flavorful and beautifully presented.