Arrange sweet potato chips evenly over base of a large, baking paper-lined roasting pan. Spray evenly with olive oil spray. Bake in a 220 °C oven (fan-forced) for about 25 minutes or until browned and tender. Turn halfway during cooking time.
Meanwhile, heat a barbecue grill to medium. Trim the stems from the mushrooms and discard. Spray the mushrooms with olive oil spray. Cook the mushrooms, top-side down, on the grill for 5 minutes. Turn and cook for a further 5 minutes or until tender. Carefully pat dry with paper towel to remove any excess moisture.
While the mushrooms are cooking, combine the mince, dill and lemon rind in a medium bowl. Divide the mince mixture into 4 even portions and shape each portion into a 10cm patty. Heat a large non-stick frying pan over medium heat. Cook the patties for 5 mins each side or until golden and cooked through. Transfer to a plate.
Combine yoghurt, garlic and lemon juice in a small bowl.
Place half the mushrooms, top-side down, on serving plates. Top with avocado, tomato, beetroot, turkey patty, yoghurt mixture and rocket. Top with the remaining mushrooms. Serve with sweet potato chips.