01 - Preheat oven to 375°F (190°C). Line a baking sheet with aluminum foil or parchment paper.
02 - Lay the turkey breast on a cutting board. Using a sharp knife, carefully slice horizontally through the thickest part, leaving the opposite edge attached. Open the breast flat and place between two sheets of plastic wrap; tenderize with a meat mallet to approximately 1/2 inch thickness.
03 - Combine goat cheese, chopped cranberries, walnuts (if using), chopped parsley, lemon zest, black pepper, and a pinch of salt in a mixing bowl. Stir until uniformly blended.
04 - Evenly spread the filling over the turkey, leaving a 1 inch border around the edges. Starting from the shorter end, roll the turkey breast tightly. Secure the roll with kitchen twine at 1 inch intervals.
05 - Rub the turkey roll with olive oil, then season the exterior with salt and pepper. Position seam-side down on the prepared baking sheet.
06 - Whisk honey, Dijon mustard, and balsamic vinegar together in a small bowl. Brush half the glaze evenly over the turkey roll.
07 - Roast in preheated oven for 35 minutes. Remove and brush with remaining glaze, then return to the oven for an additional 10 minutes, or until a meat thermometer inserted into the center registers 165°F (74°C).
08 - Let the turkey rest for 10 minutes after removing from the oven. Remove twine, slice the roll into medallions, and serve warmly.