Turn on the oven to 400 degrees.

Peel and slice the shallot thinly. Tear the sage leaves in small pieces and put both the sage leaves and shallots with heavy cream in a small pot over very low heat for fifteen minutes. Add the salt and the black pepper. Stir often and do not let the cream get to a boiling point.

Meanwhile, slice off the neck of the butternut squash and trim off the stem end of the squash. Use a vegetable peeler to peel the skin off the squash. Peel the bottom half of the squash, slice in half and scoop out the stringy pulp and seeds out. Using a mandolin or a very sharp knife, slice the squash into very thin slices, about 1/8th of an inch thick.

Taste the cream for seasoning and add more salt and pepper to taste if needed. Strain the cream and discard the solids.

Butter a 9 x 13 inch casserole dish on the bottom and sides.

Create one even layer of butternut squash in the dish, spoon on and spread a thin coating of the cream on the squash and repeat the process until the the last layer is topped with cream. Sprinkle the cheese on top of the cream evenly.

Cover with aluminum foil and bake for 35 minutes. Remove the foil and turn up the heat to a high broil until the cheese is melted and golden brown (about five minutes, but watch carefully so it doesn't burn) and take out of the oven.

Let the squash sit for 10 minutes and serve.