Cut squash in half lengthwise. Steam in ? inch water, covered on stove or in microwave, until almost tender. Cool and scoop out the pulp, being careful not to break the shell.

Cook spinach according to directions on package; drain well.

In pan, sauté green onion, parsley, celery and garlic in margarine until tender. Combine with spinach and remaining ingredients, mixing well. Stuff squash shells with the mixture. Bake for 20 minutes.