Preheat your oven to 375 F while preparing the turkey breast in Dutch oven.
Seasoned the turkey breast by first rubbing butter under the turkey breast skin, followed by sprinkling a coarse grind of brown or black mustard seed, dry or fresh minced rosemary, and cracked pepper - all slathered on the butter under the skin.
3.5 lb Split Turkey breast, ¼ cup butter, 3 tablespoon coarse brown or black mustard seed, 1 teaspoon cracked pepper, 1 teaspoon sea salt, 2 tablespoon rosemary, dry and cut
Lay a bed of onion chunks, garlic cloves, and fresh herbs on the bottom of the Dutch oven.
2 sprigs of Sage, 2 sprigs of Rosemary, 2 sprigs of Thyme, 2 medium onions, chunked, 3 cloves garlic, slivered
Add the wine (or broth) to the side of the turkey breast in the Dutch oven, not on top of it. You want about ¼" depth.
1 cup wine
Roasting the turkey breast in the Dutch oven, calculate 17 minutes per lb at 375° F when the breast is still on the bone. Roast 15 minutes per lb at 375° F if the turkey breast is boneless.
For both bone in and boneless, raise the oven temperature to 400° F the last 10 -12 minutes IF the turkey has not browned enough.
Remove when the internal temperature reaches 160° F. It will continue to cook a little from the retained heat in the cast iron Dutch oven, so for a moist dutch oven turkey, don't cook until it reaches 165° F!
Cover with the Dutch oven lid if the turkey breast is getting too brown.
Let the turkey rest for 15 minutes after your take it out of the oven, then cut. You can keep it warm simply by covering it with the Dutch oven lid completely, or cockeyed on the lower part of the pot.