Start by ensuring your whole chicken is clean and deboned. Lay the chicken skin-side down on a clean surface. If you're not comfortable deboning a whole chicken, ask your butcher to do it for you.
In a skillet, heat a tablespoon of olive oil over medium heat. Add the finely chopped leeks and onion, sautéing until they are softened and fragrant, about 5-7 minutes. Season with salt, pepper, smoked paprika, and turmeric, mixing well to incorporate the flavors.
Once the leeks and onions are ready, remove them from heat and let them cool slightly. In a large mixing bowl, combine the sautéed vegetables with the sliced tomatoes and graviera cheese sticks. Mix gently, ensuring that each ingredient is evenly distributed.
Spread the vegetable and cheese mixture evenly over the deboned chicken, leaving a small border around the edges. Carefully roll the chicken from one end to the other, tucking the filling as you go to keep everything inside.
Use cooking twine to tie the chicken roll at intervals, or use toothpicks to secure the ends. This will help maintain the shape during cooking and keep the filling intact.
Drizzle the outside of the stuffed chicken roll with olive oil and season with salt and pepper. Rub in the mustard all over the surface for added flavor and a golden crust.
Preheat your oven to 190°C (375°F). Place the stuffed chicken roll in a roasting pan and bake for approximately 1 hour or until the internal temperature reaches 75°C (165°F). Baste the chicken with its juices halfway through cooking for extra moisture.
Once cooked, remove the chicken roll from the oven and let it rest for 10-15 minutes. This allows the juices to redistribute, ensuring a moist and flavorful bite. Slice into rounds and serve warm.
