No need to preheat the oven. First make the stuffing. Place the bread crumbs, onion, thyme, mushrooms, almonds and KNORR Balsamic & Pineapple Vinaigrette salad dressing in a food processor and blitz until well combined. Stuff the mixture into the cavity of the chicken and push the half-lemon into the opening to prevent the stuffing falling out.
Massage the chicken with the dry mixture from the KNORR Cook-in-Bag sachet, making sure every bit of chicken skin is covered. Carefully place the chicken into the roasting bag and fasten the open end of the bag with the blue tie supplied. Place the bag in an oven dish and put the dish on the lowest shelf in the oven.
Turn the heat to 180 °C and roast for 50 minutes, ensuring that that grill is off at ALL times. Keep enough room for the bag to expand (it must not touch the sides of the oven).
While the chicken is roasting, prepare the gratin. Slice the sweet potatoes into 2cm-thick slices. Cut the leeks in half lengthways. Slice the cauliflower from top to bottom into ‘steaks’, reserving any florets that fall off. Grease a baking dish or roasting pan and add a layer of sweet potatoes. Top with a layer of cauliflower slices, and then a layer of leeks.
In a separate bowl, whisk together the milk, cream and the contents of the sachet of KNORR Naturally Tasty Creamy Chicken & Broccoli Bake. Season to taste with salt and black pepper. Pour half this mixture over the vegetables.
Repeat the first three layers of vegetables and scatter any remaining cauliflower florets on top. Pour the rest of the milk mixture on top. Place the baking dish [on the top shelf] in the oven and bake at 150 °C for 40 minutes, or until the vegetables are tender. Scatter the Parmesan shavings on top and bake for a further 10 minutes.
When the chicken is ready, carefully cut open the bag, baste with the juices and allow it to rest for 10 minutes before carving.
Serve the chicken with the vegetable gratin and a fresh garden salad.