Combine ½ cup beef stock, and all ingredients but the turkey legs into a saucepan over medium-high heat. Stir well as the butter melts. Once the mixture starts to boil, remove it from heat. Let cool for 10 minutes.
Then, pour into a deep casserole dish and place turkey legs inside. Cover and allow to marinate overnight, or at least 5 hours.
Remove turkey legs from the casserole dish and set them aside. Pour the marinade into a large mixing bowl with a pour spout. Set aside ½ cup, and pour remaining marinade into a saucepan.
Bring to a boil for 3 minutes. Remove from heat and place into a bowl for basting.
Set smoker to 250°F and preheat for 15 minutes with the lid closed. Fill auger ½ full with cherry wood pellets.
In a small mixing bowl combine the ½ cup of marinade set aside in step 2 with ½ cup beef stock.
Use a meat injector to inject marinade into the meatiest parts of the turkey legs.
Place turkey legs directly onto the grill grates. Cook for 3 hours. Baste or brush with the boiled marinade every 30 minutes.
Remove from heat once the internal temp has reached 165°F.