Place the flour in a plastic bag, add the chicken and toss to coat evenly. Remove from the bag and shake off any excess flour.
In a heavy casserole dish over medium heat, place the olive oil and butter. When the butter is foaming, add the drumsticks and brown for 3 minutes on each side. Add the lemon, garlic, olives, capers, wine and stock, bring to the boil and then transfer the dish to the oven and cook for 30 minutes until the chicken is ready to fall from the bone. Keep warm.
Bring a large saucepan of lightly salted water to the boil, add the spaghetti and cook until just al dente. Drain.
In a separate pan, heat the oil and sauté the garlic and chilli until the garlic just begins to brown, then add the salt. Remove from the heat and add the drained spaghetti, then stir in the butter and parsley. Divide the spaghetti between the serving plates and top with the chicken and sauce. Grate over the Parmigiano-Reggiano and add a grind of black pepper if desired.