Place the drumsticks in a pot and add enough chicken stock to mostly cover them. Bring to a gentle simmer.
Cook for 25 to 30 minutes, until the chicken is cooked through and reaches 165°F in the thickest part.
Remove the drumsticks from the stock. Let them cool slightly, then pat very dry with paper towel.
Simmer the remaining cooking liquid until reduced to about 1 1/2 cups.
For the gravy, melt the butter in a small saucepan. Stir in the flour and cook for 1 to 2 minutes. Whisk in the reduced chicken liquid gradually. Simmer until smooth and lightly thickened. Season to taste.
Mix the milk, lemon juice, and salt. Let sit for 5 minutes.
In a separate bowl, mix the flour, salt, garlic powder, onion powder, paprika, turmeric, black pepper, and cayenne if using.
Dip each drumstick in the buttermilk, then into the seasoned flour. Repeat once more for a double coating. Press the flour on gently.
Rest the coated chicken on a rack for 10 minutes.
Heat the frying oil to 350°F. Fry the drumsticks for 4 to 6 minutes, until the crust is golden, crisp, and hot inside.
Drain on a rack. Serve hot with the brown gravy and fries or coleslaw.