•Preheat the oven to 200°C.
•Place the chopped onions and finely chopped garlic on a baking tray.
•Lay sardines on the onions and garlic in a single layer.
•Put the slices of tomato and lemon sliced into large circles over the fish.
•Drizzle olive oil and add rosemary and bay leaves.
•Finally, add black pepper and salt and cover your tray with aluminum foil.
•Bake for 20-25 minutes until the sardines are cooked through. Your delicious and healthy fish is ready. Enjoy!