Cut squash in half lengthwise and scoop out the seeds. Brush a small amount of oil on the cut edges of each squash half. Spray a baking sheet with vegetable cooking spray. Place each squash half, cut side up on the baking sheet, cover tightly with foil and bake in a preheated 400 degrees F oven, until tender, about 35-40 minutes.

Over medium heat, cook sausage until it is no longer pink, breaking the sausage into small pieces. Drain sausage, if necessary. Reserve 2 tablespoons pan drippings and discard remaining pan drippings.

Over medium heat, cook celery in reserved pan drippings for 5-7 minutes, add apple and continue to saute.

Remove from heat and stir in reserved sausage, bread crumbs, sage and sugar.

When squash is cooked, remove from oven and reduce oven temperature to 350 degrees F. Cool squash until shells can be handled. Scoop out the pulp, leaving a 1/2-inch shell. Combine squash pulp with sausage mixture.

Mound sausage mixture into squash shells. Top each with 1-tablespoon apple jelly. Return to the 350 degrees F oven and bake uncovered until mixture is cooked through, about 25 minutes.