Squash Gratin Recipe

Preheat the oven to 400 degrees. In a steamer set over boiling water, steam the squash, covered, for 15 minutes, or until it is tender. In a food processor puree the squash with the butter, season it with salt and pepper, and transfer it to a buttered 2 to 3 cup shallow baking dish,
smoothing the top. Sprinkle the top with the walnuts and the Parmesan and bake it for 15 minutes, or until the cheese is melted and the walnuts are toasted.