1) Preheat the oven to 200°C/gas mark 6.
2) Place the butternut squash on a sheet pan. Add 2 tablespoons of olive oil, the maple syrup, 1 teaspoon of salt and 1/2 teaspoon of pepper, and toss. Roast the squash for 15 to 20 minutes, turning once, until tender. Add the cranberries to the pan for the last 5 minutes.
3) While the squash is roasting, combine the apple cider, vinegar and shallots in a small saucepan and bring to a boil over medium-high heat. Cook for 6 to 8 minutes, until the liquid has reduced to about 90ml. Remove from the heat, whisk in the mustard, olive oil, 1 teaspoon of salt and 1/2 teaspoon of pepper.
4) Place the rocket in a large salad bowl and add the roasted squash mixture, the walnuts and the grated cheese. Spoon just enough vinaigrette over the salad to moisten and toss well.
Sprinkle with salt and pepper and serve immediately.