Cook spinach according to package directions. Drain and reserve liquid. Melt margarine in saucepan. Add flour, stir until blended and smooth, do not brown. Add onion and cook until soft not brown. Add liquid slowly, stirring constantly. Cook until smooth and thick.
Add seasonings and cheese. Stir until melted. Combine with cooked spinach. Put in buttered casserole, top with buttered bread crumbs. Flavor is improved if this is left in refrigerator, covered, overnight. This may also be frozen. Bake at 350F for one hour. Two pints small oysters drained, may be added when you add the cooked spinach.
Cajun Country -- New Iberia, Louisiana