Food and Wine publishes a recipe for garlic soup by Susan Spicer at FoodAndWine.com. The recipe calls for olive oil, butter, onions, garlic cloves and chicken stock as well as fresh herbs and half-and-half. The soup is garnished with croutons.
Heat 2 tablespoons of olive oil and 2 tablespoons of butter together in a large pot over low heat. Add 2 pounds of chopped onions and 2 cups of chopped garlic cloves, cover, and cook while stirring occasionally. After the onion and garlic become very soft and start to turn golden (about 30 minutes) raise the heat to medium and continue cooking the onions and garlic uncovered for about 10 minutes until they turn deep golden.
Add 2 quarts of chicken stock, 1/2 loaf of day-old bread cut into chunks, a bouquet garni of 6 parsley stems, 9 springs of fresh thyme and 1 bay leaf, and 1 1/2 teaspoons of salt to the pot. Bring to a boil, reduce the heat to a simmer and continue to cook for about 15 minutes.
Remove the bouquet garni and transfer the soup to a blender or food processor. Puree the soup until smooth. Pour the soup back into the pot through a strainer, add 2 cups of half-and-half and 1/4 teaspoon of freshly ground black pepper and bring back to a boil. Serve the soup hot, topped with croutons.