Cut squash in half, vertically. Remove seeds.

Place squash, cut-sides down, in a nine- by 13-inch baking pan. Add about half an inch of water to the bottom of the pan. Bake squash with water, uncovered, for 30 to 40 minutes. Drain and cool slightly.

Preheat oven to 400 degrees Fahrenheit.

Scoop out some of the squash into a bowl, leaving 1/4-inch thickness in the shells. Mash removed squash; add orange juice, brown sugar, and allspice. Stir well.

Cut a thin slice from bottom of each squash shell, so that it will sit flat. Coat baking pan with oil or cooking spray and return squash to pan. Spoon mashed squash mixture into shells.

Combine corn flake crumbs, pecans, and margarine. Sprinkle crumb mixture over squash.

Bake, uncovered, at 400 degrees Fahrenheit for 15 to 20 minutes or until heated through.