Remove from heat & stir in breadcrumbs, cheese, herbs & 1/4 tsp each salt & pepper; set aside.
Herb Butter
In a small dish, combine all herb butter ingredients & set aside.
Preheat oven to 350 F.
Assembly
Arrange turkey breast skin side down on a work surface so that it lies open & flat. Cover with plastic wrap, then pound lightly with a meat mallet to flatten & make an even thickness all over.
Discard plastic wrap & season turkey all over with remaining salt & pepper.
Spread stuffing over turkey, leaving a 3/4-inch border around the edge. Close up snugly, tucking in the stuffing as you go, then tie with kitchen twine at 1-inch intervals around the entire turkey breast.
Rub turkey all over with herb butter & arrange it on a rack in a roasting pan.
Roast uncovered, basting occasionally, until turkey reaches an internal temperature of 180 F. about 2 hours. (Cover with foil if top browns too quickly).