- Preheat oven to 180C. Preheat water bath to 60C. Preheat deep fryer to 170C.
- Remove breasts from chicken, discard skin. Remove thigh meat from skin and bones, cut into 1.5 cm pieces and reserve. Roughly chop carcass and bones and reserve.
- To make the roulade stuffing, place 2 tablespoons butter in a frypan and set over medium heat. Once melted, add shallots, apple, mushrooms and 4 sprigs thyme and cook until softened. Remove from heat.
- Butterfly chicken breasts. Lay down pancetta slices on a piece of plastic wrap and top with chicken breast. Add stuffing and roll tightly. Place in water bath and cook until just cooked through, about 35 minutes.
- To make the sauce, place 1 tablespoon oil in a saucepan and set over high heat. Add chicken bones and carcass and cook until brown. Add roughly chopped carrot, celery and onion and cook until browned. Add stock and 6 sprigs thyme and bring to a boil. Allow to simmer, skimming fat from top occasionally until reduced, about 40 minutes. Remove from heat and strain into a clean saucepan. Add 80 grams cold, diced butter and whisk until melted. Set aside, keeping warm.
- Peel remaining 4 onions and cut into flowers by making cuts all the way around but not all the way through. Place in the oven to bake until charred on the ends.
- Place grated carrot, 40 grams butter, 2 sprigs thyme and ¾ cup water in a saucepan and set over medium heat. Cook until carrot is soft. Remove from heat, transfer to a blender and process to a smooth puree. Pass through a sieve into a clean saucepan, season and set aside.
- Place flour, 1 teaspoon salt and chilli powder in a bowl and stir to combine. Place the milk in a bowl. Dip chicken thigh pieces in flour mix then milk then back in flour to coat.
- Place chicken, carrot and celery in deep fryer to fry until golden. Remove from oil and drain on paper towel.
- Place 1 tablespoon oil in a fry pan and set over medium heat. Remove chicken from plastic wrap and place in fry pan. Fry until browned on all sides. Remove from heat and allow to rest.
- To serve, slice chicken and place on serving plates. Add carrot puree, onion flower, crispy chicken, carrot and celery salad and drizzle with sauce.