Cream of Spinach Soup

1/4 Cup margarine
1 Onion, chopped
4 Cups chopped spinach
2 Medium carrot, peeled and sliced
2 Medium potatoes, peeled and diced
2 Tablespoons lemon juice
5 Cups chicken broth
1 Cup heavy cream
1 Teaspoon salt
1/4 Teaspoon pepper
Melt margarine in a large pot, add the onion, carrots, and celery, and cook for 15 to 20 minutes, stirring from time to time. Add the potatoes and spinach, stir until coated. Stir the broth and cook, partially covered, until potatoes are tender, about 20 minutes. Put into a blender and blend until smooth. Return to pot, stir in cream and lemon juice. Add salt and pepper. Reheat without boiling. Serve hot. Serves 8.