DO-AHEAD TIP: Marinate turkey overnight or for at least 4 hours (see recipe).
Place lemon juice, garlic, and turkey in a large zipper-topped plastic bag; seal bag and refrigerate overnight or for at least 4 hours.
At time of cooking, remove turkey cutlets from bag (discarding bag and marinade) and sprinkle evenly with salt, pepper, onion powder and sage.
Melt the ghee or coconut oil in a large skillet over medium-high heat; add turkey fillets and cook for 4 to 6 minutes per side or until cooked through.