With a sharp knife, butterfly each breast open to lay flat.
Place each breast between two sheets of waxed paper, and flatten with a mallet.
In a bowl, combine the apple, dried cranberries, walnuts, mushrooms, bacon, rosemary, thyme, and season with salt and pepper to taste. Toss until well mixed.
Spread the apple-cranberry stuffing on top of each breast, up to to 1/4-inch from the edge.
Roll up each breast tightly and tie with cooking twine.
Season the rolled breasts generously on all sides.
Heat some cooking fat in a large ovenproof skillet placed over medium-high heat.
Brown each turkey breast on all sides, 2 to 3 minutes per side.
Place the skillet in the oven, uncovered, and roast for 45 to 60 minutes.
Allow the breasts to rest for 5 to 10 minutes before slicing and serving.