Steamed fish fillet

Ingredients:
1 fish fillet, you can use any fish fillet you like.  I used tilapia fillet
1 onion, sliced into rings
1 tomato, sliced into rings
salt and pepper to taste
1 tbsp butter
Minced cilantro

Procedure:
Preheat oven at 350 degrees Fahrenheit for 15 minutes.  Rinse and pat dry fish fillet.  Season with salt and pepper.  Put it in a foil.  Brush butter on top.  Top it with the onion rings and tomato rings.  Sprinkle minced cilantro.  Tightly cover foil and bake it in the oven for 20 minutes.  After 20 minutes, oven foil and bake for another 10 minutes.  Transfer on a serving dish and serve.