Soak the rice in cold water for 2-3 hours.
Prepare the marinade for the chicken legs: combine olive oil, barbecue sauce, soy sauce, chopped cilantro and dried garlic. Coat the chicken legs evenly with the marinade and let them sit for 2-3 hours.
Preheat the oven on top and bottom heat to 230°C.
Place rice in a prepared ceramic baking dish, add pieces of butter, thyme sprigs and peeled garlic. Spread the rice evenly over the surface and place the chicken legs overlapping each other on top. Pour water over the rice until the liquid just touches the chicken. Place the pan with the rice in the oven on the middle rack, add water to the bottom tray and bake for 25-30 minutes until the chicken forms a crust. Remove the pan with rice and chicken. Using tongs, turn the drumsticks over and check the rice for firmness and water level.
If the rice is still hard and the water has completely evaporated, add a little more. Place the pan in the oven, reduce the temperature to 180°C and turn on the convection mode. Bake the dish for another 15 minutes until golden brown.
Check the chicken and rice for doneness and remove the roasting pan from the oven. Serve for a large family feast.