In a food processor, combine the chiles, butter, garlic and the chopped scallions and puree until smooth. Season generously with salt and pepper. Carefully loosen the turkey breast skin and rub one-third of the ancho-scallion butter over the meat. Rub the remaining butter all over the top skin and bottom of the turkey breast. Season with salt and pepper. Let the turkey breast stand at room temperature for 1 hour.