
Pre-heat oven to 425F (210C). Lightly oil or line with parchment paper a medium baking dish.
Place cut side up onions in a single file in baking dish, sprinkle with minced garlic, oregano, salt, chopped rosemary and drizzle with olive oil.
Bake for approximately 30-30 minutes or until onions are tender and dark golden brown. Serve immediately. Enjoy!