In a saucepan, cover the chicken with the water. Bring to a boil and simmer very gently for about 10 minutes. Remove the saucepan from the heat. Cover and let stand for 10 minutes. Drain the chicken and keep the cooking juices. Cut the chicken into cubes.
In a food processor, purée the chicken with about 180 ml (3/4 cup) of cooking liquid (or more, depending on the desired texture) until smooth.