Prepare whole mushrooms; chop fine. Add 1 Tbls butter, onion, and celery seeds. Simmer covered 5 min. Add bouillon cubes, boiling water; simmer, uncovered 10 min.
In a double-boiler top over direct heat, melt 1 Tbls, butter. Add flour; stir still smooth. Add milk, salt, pepper. Cook over boiling water, stirring till thickened. Add mushrooms mixture; heat. Makes 6 servings.