In a large food-safe container, dissolve the kosher salt, brown sugar, and Prague Powder #1 in 1 gallon of cold water. Stir until all solids are fully dissolved to create the brine.
Submerge the turkey legs completely in the brine. Refrigerate for a full 24 hours to allow the cure and salt to penetrate the dense meat.
After brining, remove the legs, rinse them under cold water, and pat completely dry with paper towels. Place on a wire rack and air-dry uncovered in the refrigerator for 2-4 hours to develop a tacky surface (pellicle).
Preheat your smoker or grill for indirect cooking to a steady 250°F. Add your choice of smoking wood, such as cherry, apple, or hickory.
Place the dried turkey legs directly on the smoker grates. Smoke uncovered for approximately 2 hours until they develop a deep, mahogany color.
Remove the legs from the smoker. Wrap each leg tightly in heavy-duty aluminum foil. You can add 2 tablespoons of chicken broth or melted butter to each foil packet before sealing to add moisture.
Return the wrapped legs to the smoker. Continue cooking for another 1-2 hours, or until an instant-read thermometer inserted into the thickest part of the meat (avoiding the bone) registers 185-190°F.
Once the target temperature is reached, carefully unwrap the turkey legs and serve immediately.