For the filling 20ml extra virgin olive oil 10g salted butter ½ tsp sea salt ½ tsp paprika ½ tsp dried thyme ½ tsp mustard powder 500g skinless chicken breast fillet 300g mushrooms, cut into 1cm slices 1 small onion, diced 1 leek, white part only, cut into 8mm slices 2 garlic cloves, crushed 1 tsp chopped thyme 300ml chicken stock 3 tsp cornflour mixed to a paste with 30ml cold water 125ml pouring cream, whisked together with 1 egg yolk 3 tsp lemon juice sea salt, to taste Preheat the oven to 200C fan-forced (220C conventional). Heat the oil and butter in an 18 x 28cm flameproof baking dish, 5cm deep, for 5 minutes. Meanwhile, combine the salt, paprika, thyme and mustard powder in a small bowl, then rub all over the chicken breast. Add the chicken to the hot dish and bake for 5 minutes, then turn and bake for 5 minutes more, or until just cooked through. Remove from the oven, cut the chicken into 1cm pieces and set aside to cool. Add the mushrooms, onion, leek, garlic and chopped thyme to the dish and stir to coat with the chicken juices. Heat over medium heat and saute until the onion is soft, about 3 minutes. Stir in the chicken stock and bring to the boil. Thicken with the cornflour paste, boiling for 1 minute more. Remove from the heat and stir in the cream mixture and the lemon juice, then add the chicken pieces. Add sea salt, to taste, and set aside to cool.
