- At least one week before cooking your turkey, make your own tarragon vinegar. Fill a large mason jar with fresh tarragon, then bruise them a bit to release the essential oils. Fill the container with a light vinegar. Close the lid and let sit for a week. You can also buy premade tarragon vinegar.
- One day before grilling, soak the turkey breast in a basic brine to add moisture and flavor to the meat: In a large nonreactive pot (use plastic, glass, or stainless steel as other metals can react to the brine and give the meat a metallic taste), combine water, salt, and sugar. Mix thoroughly to dissolve. Macerate berries and add to brine (we used Florida strawberries, but you can use berries of your choice). Then add tarragon vinegar, garlic, pepper, coriander, and thyme. Add the turkey breast and let sit in the brine for 24 hours.
- Remove turkey from brine, rinse and pat dry, then coat with olive oil and grill over indirect heat (about 325 degrees) for approximately 4 hours, turning or flipping the bird every hour. The exact cooking time depends on the size of the turkey: expect 15 minutes per pound. The turkey is done when the internal temperature reaches 165 degrees.
- When done, let rest for 15 minutes before carving, then place on a bed of patted butter and fresh thyme sprigs. Cover to keep warm, then serve.