Preheat your oven to 325°F (165°C).
In a bowl, mix together the miso paste, maple syrup, softened butter, soy sauce, and black pepper to form a smooth paste.
Gently loosen the skin on the turkey breast by sliding your fingers between the skin and the meat. Rub half of the miso maple butter mixture under the skin, spreading it evenly over the breast meat. Rub the remaining mixture all over the outside of the turkey.
Stuff the cavity of the turkey with the fresh herbs, lemon halves, and crushed garlic.
Place the turkey on a roasting rack inside a roasting pan. Roast in the preheated oven, basting occasionally with the juices, until the turkey is golden brown and a meat thermometer inserted into the thickest part of the thigh reads 165°F (74°C), about 3 hours.
Remove the turkey from the oven and let it rest for at least 20 minutes before carving. This will allow the juices to redistribute and ensure the meat remains juicy.