Boston Market Creamed Spinach

10 3/4 can cream of celery soup
1 tbs. flour
1/4 cup butter or margarine or canola oil
1/2 tsp. garlic salt or to taste
Salt to taste
Pepper to taste
20 oz. frozen chopped spinach, cooked according
to package directions, well drained OR
2 pounds fresh spinach, cleaned, stems removed,
chopped, cooked and drained
1 tblsp dry onion, chopped, OR
1 small onion, peeled, ends removed, diced
In a large saucepan over medium heat, whisk together celery soup, flour,
butter or margarine or canola oil, garlic salt, salt and pepper until smooth
and piping hot. Add cooked and drained spinach, dry chopped onion or diced
onion. Serve.