- In a skillet, melt butter on medium heat. Add onion and sliced mushrooms. Cook until tender.
- Add the spinach, salt, and pepper, and stir until cooked and wilted. Remove from the heat and let it cool to room temperature.
- Put the mushroom and spinach mixture in a food processor and pulse so it is evenly minced but not overly processed.
- Holding the knife horizontally, insert into the thick end of each chicken breast and cut to make a deep pocket. Be careful not to pierce through the other end.
- Spoon the mushroom and spinach mixture evenly into the pockets of each chicken breast.
- Wrap each stuffed chicken breast with two slices of bacon. Place on smoker rack.
- Set the smoker to 250ºF using Bradley Premium Sage Bisquettes (or Hickory Bisquettes).
- Smoke the chicken until they reach an internal temperature of 165ºF.