Set up your barbecue for direct cooking. Place a casserole dish (without lid) in the centre of the grill and add 2 tablespoons oil. Preheat on high for 10 minutes.
Oil the drumsticks and season them with salt and pepper.
Once the barbecue is preheated, leave the heat setting on high. Add the onions and garlic to the casserole dish and cook for 2 to 3 minutes, stirring occasionally. At the same time, add the chicken to the grill and cook for 2 to 3 minutes per side. Once you have turned the chicken, remove the casserole dish from the barbecue.
Related Grill Skills
Chopping an Onion
Add the undrained tomatoes and stock to the casserole and stir through.
Turn your barbecue to the roast setting (add a convection tray and trivet if using a Q) using tongs and/or heatproof gloves. Place the lid on the casserole dish and place on the barbecue. Cook for 1 hour.
Remove the casserole dish lid and cook until the chicken is tender and the sauce has reduced and thickened slightly, a further 25 to 30 minutes.
Add the olives, parsley, and oregano and cook until heated through, a further 5 to 10 minutes.