Combine the lemon peel, water, and sugar in a small pot and heat over medium flame. Bring to a boil and simmer for 3 minutes. Remove from heat and set aside.
Heat 2 tablespoons of the olive oil in a large skillet over high heat. Add onions and cook until gently browned. Add garlic and cook for another minute. Toss into a 5-quart Dutch oven.
Heat another 1 tablespoon of olive oil over high heat, add sweet potatoes and cook until they are brown on all sides. Add to Dutch oven.
Add remaining 2 tablespoons of olive oil to the skillet, still over high heat. Add carrots and celery, cooking until they have browned a bit on all sides. Toss into Dutch oven. Stir in salt, pepper, and lemon peel.
Add sausage to the skillet and turn heat to medium. Cook until it releases its fat, about 5 minutes, stirring occasionally. Remove sausage, allowing the fat to remain in the pan, and sprinkle sausage meat around the vegetables in the Dutch oven. Lay herbs across the surface of the vegetables and meat.
Truss the chicken and rub it down with salt and pepper. Place it in the hot pan, still on high heat, and brown well on all sides until crispy. Tuck the chicken into the Dutch oven, surrounded by vegetables. Mix together stock and white wine, and pour over chicken and veggies.
In a small bowl, combine flour* and enough water to make a stiff dough. Turn dough out onto a floured surface and roll into a long, 1-inch thick sausage-shape. Run the dough around the rim of the Dutch oven, making a thick border around the whole thing. If it breaks, that’s fine — just piece it together with more dough. Press the lid onto the Dutch oven and slide into the preheated oven.
Bake for 1 hour.
Break seal and serve hot with a huge helping of vegetables.
*If using gluten-free ingredients for the dough seal, replace flour in this recipe with the following: 2 cups gluten-free flour mix 1/2 teaspoon xanthan gum only if using gluten-free flour