Pound each chicken breast on a cutting board, covered with cellophane, using a mallet, until roughly 3/8” thick and roughly 4 ½” x 6”. They may be slightly larger or smaller depending on the chicken breast size, but making them roughly the same size will allow them to cook through at the same time.
Set the flattened chicken breasts on a large plate or platter and sprinkle with salt and pepper.
Spread ½ - 1 teaspoon pesto on each chicken piece, leaving a half inch to the edge without any pesto.
Add 1/4 - 1/3 cup of the rice stuffing.
Sprinkle a third or fourth of the Pecorino cheese over the rice stuffing.
To roll, fold in the edges of the chicken, while rolling to cover the stuffing. Skewer through the chicken several times near one end, like sewing, then into the other end to seal closed. Repeat with a second skewer starting on the other end.
Set on a buttered or greased baking sheet or cast iron skillet. Place a pat of butter on each piece. Repeat for remaining pieces of chicken. Salt and pepper the outside lightly.
Bake at 400 degrees for 25 minutes, then increase temp to 425 and bake for 5- 8 minutes more, until chicken is lightly browned.
Remove skewers and place chicken on a platter or individual plates to serve. Top with heated sauce and additional Pecorino Romano cheese.