Preheat the oven to 180°C.
Cut the squash in half lengthwise, then scoop out the seeds and fibrous bits.
Rub both halves with a drop of oil and put them on a baking tray.
Bake for about 30 minutes or until a fork goes through the flesh easily.
Take the tray out of the oven and let it cool.
Meanwhile, thinly slice the onion.
Heat drop of oil in frying pan and gently sauté the onion and rosemary, until softened. Add the shredded duck meat, chopped mushrooms and gravy. (If you don’t have any leftover gravy, add some stock powder and water).
When the squash is cool enough to touch, scoop out the flesh, leaving a thin layer of squash under the skin.
Put the squash flesh into a mixing bowl, then add the onion and duck. Crumble most of the cheese on top, then mix well to combine. Taste and adjust the seasoning. You can add a pinch of chilli flakes, if you like.
Spoon this mixture into the squash skin, then scatter the remaining cheese on top.
Put the tray back into the oven and bake for another 10-15 minutes or until the cheese has melted.
Scatter the parsley leaves on top and serve.