Spinach and Yogurt Soup Recipe

Ingredients

• 1 1/2 tablespoons butter or margarine
• 1 medium onion, finely chopped
• 2 teaspoons all-purpose flour
• 1/3 teaspoon salt
• 1/4 teaspoon dried tarragon
• 1 pinch ground nutmeg
• 1 pinch cayenne pepper
• 1 (16 ounce) package frozen chopped spinach, thawed
• 2 cups chicken broth
• 3/4 cup plain yogurt
• 2 slices lemon, cut in half for garnish