By James Peterson
You can bake the squash the day before or earlier the same day you make the gratin.
Put the squash on a sheet pan in the oven and turn the oven to 375°F (there is no need to preheat). Bake for about 40 minutes, or until a knife slides easily into the squash. Let cool. Leave the oven on.
Cut the squash in half lengthwise. Using a