Warm half the olive oil in a frying pan over a medium heat. Add the onion, garlic and tomatoes and sauté for 2 to 3 minutes.
Pour in the egg and move the pan around so that the egg covers the base. Season with salt and pepper. Fry for couple of minutes and when it’s lightly brown flip it over and leave for another 1 to 2 minutes. Allow to cool completely.
Lay the chicken skin-side down on a cutting board, and cover with cling film. Using the meat hammer pound the chicken several times until flat throughout. Season generously with salt, pepper and BBQ seasoning. Lay the omelette on the top of the chicken.
Gently roll up the chicken, starting from the side closest to you and secure with kitchen string. Rub the chicken with the remaining olive oil and extra seasoning. Place on a rack in a roasting pan.
Bake in the preheated oven to 1 to 1 1/2 hours until golden brown and the chicken is no longer pink in the centre.