Trim the stem end from each squash so it will sit upright. With a melon baller, remove the brown portion of the blossom end and discard. Continue to hollow out the seed cavity, retaining the trimmings, until you have a shallow bowl 1/4 to 1/2 inch thick on all sides. As the squash are prepared, place them in a lightly oiled baking pan.
Melt the butter in a skillet, add the celery and scallions and saute five minutes, add the squash pieces and continue cooking until they are tender.
Transfer the cooked vegetables to a bowl and add the remaining ingredients. Mix well.
Stuff each squash with about 1/4 of the stuffing mixture. (Any remaining stuffing can be placed in a ramekin and baked alongside the squash.).
Bake until the squash is tender and the stuffing is golden brown on top, about 30 minutes.