Preheat your oven to 200 C / 400 F. Line a baking sheet with parchment or a silpat.
Split the squash in half and scrape the seeds out. Split the halves in to quarters, brush with olive oil, then sprinkle with salt and pepper. Set on the lined baking sheet and slide into the oven to roast for about 10 minutes.
Rinse the squash seeds under water, pat dry, then put them in a bowl and drizzle with some olive oil. Remove the squash from the oven, add the seeds to the baking sheet, sprinkle with salt and pepper, and replace in the oven.
Roast everything for an additional 20-30 minutes, until the squash is golden and tender and the seeds are golden and crisp.
While the squash is roasting, whisk together olive oil, balsamic vinegar, mustard, salt and pepper. Toss the dressing with the greens.
When the squash is done, remove from the oven and set onto serving plates. Spoon the salad into the hollow of the squash, then sprinkle with roasted seeds and crumbles of cheese. Serve.