For the dorado with lecho vegetables, wash the dorado, pat dry and season with salt, lemon juice and garlic inside and out. Roast in the oven at 180° C for about 45 minutes.
In the meantime, cut the onion and bell bell pepper into pieces and fry them briefly in a little oil. Add the strained tomatoes. Season with salt, pepper, garlic and possibly a pinch of sugar.
Simmer on low heat for 15-20 minutes. Serve the gilthead with the lecho vegetables.
Serve the gilthead with potatoes or rice.