Thaw the turkey breast completely in the refrigerator overnight.

Combine softened salted butter, white vinegar, orange juice, and orange zest into a medium bowl and mix well.

Pat the turkey breast dry with paper towels to remove excess moisture.

Mix dried rosemary, sage, thyme, celery salt, garlic powder, dried minced onion, smoked paprika, black pepper, and red pepper flakes in a small bowl.

Coat the turkey breast with the chilled citrus butter, rubbing it under the skin.

Sprinkle the seasoning mix evenly over the turkey breast.

Preheat the smoker to 225°F.

Smoke the turkey breast for approximately 3 hours, until the internal temperature reaches 160°F.

Remove from the smoker and let it rest for about 10 minutes before slicing.