Make certain that no fragment of bone remains attached to the breast. Open them out, separating the filet from the filet mignon to form an approximate heart shape, flatten with the side of a cleaver or a large knife, and spread them out on a platter covered with all the ingredients except salt. Turn them around and over several times during a 1- or 2-hour period. Salt each filet lightly, coat well with the chopped vegetables from the marinade, roll it up carefully, and fix with 3 or 4 toothpicks. Salt the outside lightly and grill on a preheated grill for from 10 to 12 minutes, turning them every 2 or 3 minutes and basting regularly the colored surfaces, adding more olive oil to the marinade if necessary.