Paella is cooked in a paella pan, which is a large, shallow, flat pan. An important part of the flavor comes from the addition of saffron and the sofrito, or the combination of tomatoes, and garlic (and sometimes peppers). First the meat, and then the vegetables are stir fried in olive oil; subsequently water is added and brought to a boil, and left boiling for half an hour or so. (This, however, is not the sole method utilized in the preparation. Many chefs add the water, allow it to come to the boil and at that moment add the rice.) Later, after checking the obtained broth flavour and adding salt if required, the rice is added. The rice in Valencian paella is never stir-fried in oil, as pilau, though the paella made further southwest of Valencia often is. Once the rice is nearly done, the paella is removed from the heat and left to absorb the remaining water. Traditional paella has a crispy, caramelized, toasted bottom (called socarrat in Valencian) that is considered a delicacy. To achieve a socarrat, one either needs to time the evaporation of the water properly with the completion of the rice being cooked or turn up the heat to high and listen to the bottom of the rice toast. Once the aroma of toasted rice comes from the pan, but before the rice burns, the heat is removed once again. The paella is ready to be served after having cooled for several minutes.