Preheat the oven to 425°F. Set a wire rack inside a large roasting pan. Pat the turkey breast dry with paper towels and place it on the rack.

Rub the softened butter all over the turkey breast until completely coated. Press the chopped herbs into the butter, then season generously with kosher salt and freshly cracked black pepper.

Roast the turkey for 30 minutes until the skin is golden and crisp.

Reduce the oven temperature to 325°F and continue roasting for 1 1/2 to 2 hours, until the juices run clear and an instant-read thermometer inserted into the thickest part of the breast registers 160°F. Tent the skin loosely with foil halfway through if it starts getting too dark.

Transfer the turkey to a cutting board, cover it loosely with foil, and let it rest for about 15 minutes.

Slice the rested turkey with a sharp knife and serve with the cranberry mostarda and brown butter sauce.

In a small bowl, combine the yellow mustard seeds with the white wine and white wine vinegar. Let soak at room temperature for 1 hour.

In a 2-quart saucepan, whisk together the soaked mustard seed mixture, sugar, sparkling white grape juice, cranberry juice, and mustard powder. Bring to a boil over medium heat.

Reduce the heat to medium-low, add the cinnamon sticks and star anise, and simmer gently without stirring until the syrup coats the back of a spoon, about 25 to 30 minutes.

Stir in the dried cranberries and a pinch of salt. Let the mostarda cool completely, then refrigerate until ready to serve. It can be refrigerated for up to 1 week.

In a small saucepan, melt the butter over medium heat. Reduce the heat to medium-low and cook, swirling frequently, until the butter becomes deep golden brown and smells nutty, about 8 to 10 minutes.

Stir in the chopped herbs and a pinch of salt. Serve the brown butter sauce warm over the sliced turkey.