Preheat the oven to 350 degrees Fahrenheit (180 degrees Celsius).
1 Medium Butternut Squash
Prepare your butternut squash. Cut it in half and scrape out the seeds. Discard the seeds. I use a knife and a small spoon or a grapefruit spoon to loosen the seed pod. Peel the squash and cut it into larger, same-sized chunks.
Arrange the butternut squash chunks in a baking dish.
Roast the squash chunks in the oven for about 20 to 25 minutes or until tender.
In the meanwhile, prepare the cream egg filling. In a bowl, combine the egg, the pepper, the salt, the thyme, the rosemary, the cream, the shredded cheese, and the mustard with a whisk.
Pour the cream egg filling over the roasted butternut squash in the baking dish. Spread it out evenly so that all corners are covered.
Sprinkle some olive oil over the dish.
1 Tablespoon Olive Oil
Bake the butternut squash casserole for about 25 minutes in the oven uncovered at 350 degrees Fahrenheit (180 degrees Celsius) or until golden at the top and cooked.