preheat oven to 375 degrees
In sauce pot combine 1/2 stick butter, pie spices and sage, cook over low heat for a few minutes to melt butter and infuse with flavors of sage and spices.
Add flour while whisking and cook for 2 minutes, then add milk, whisk briskly to incorporate and remove any lumps.
Add chives, cook for 2 minutes, as sauce starts to thicken slightly reduce heat to low and whisk in the cheese to melt and make sure it's smooth. Consistency should be enough to coat a spoon but too thin to build a stone wall.
In a greased baking dish or roasting pan add squash and apples, ladle sauce over.
In small work bowl add 1/2 stick (melted) butter, parmesan cheese and bread crumbs, mix well. Toss mixture on top of gratin, cover with foil and place in the oven for 35 minutes.
Remove foil, continue baking until some light golden browning happens and ingredients are tender when pierced with a knife.
Allow to cool at least 30 minutes at room temp before serving.