Roughly chop the onions and mince the garlic. Saute them in olive oil in medium heat and cook the onions down.
Add bay leaves, tomato sauce and blended tomatoes. Add sea salt and black pepper.
Once sauce is fully cooked, add to baking dish. Preheat oven to 400 degrees F.
Sea Bream
Fish needs to be gutted and cleaned. Pat the fish dry with paper towel, season thoroughly on both sides with sea salt, pepper, lemon juice and herbs of your choice. Cut 3 slits on each side and add lemon slices in each for more flavor. Fill the cavity of lemon and rosemary (other herbs of your choice too if you like).
Place seasoned sea bream over the tomato and onions sauce, nestling them in. Alternate head and tails so they all fit.
Bake at 400 degrees F for about 30 minutes. If you like the fish to have a bit of charr on the skin, bake for 25 minutes at 400 F and another 5 minutes switch to broil. Serve with your favorite salads and more fresh lemon slices. Enjoy:).
Video
Notes
Usually 3 fish of this size are enough for a family of 4 (with kids). If all your guests are adults, I'd get 1 fish per person.
Preferably buy the fish already gutted and cleaned (Costco sells them clean like this) or ask the fishmonger to do it for you.
Nutritional values are automatically calculated, use them as guidance but for more accurate values measure the weight and use a calculator.