Portuguese Cilantro Potato Soup

From David Glass:

I first has this sensational soup in Oporto, Portugal and it was live after the first spoonful. I later found a recipe in Jean Anderson’s “The Food of Portugal”. As an aside, anyone interested in Portuguese cuisine should own this classic cookbook!

4 onions, coarsely chopped
2 garlic cloves, minced
4 Tablespoons olive oil
4 medium-sized new potatoes, peeled and chopped
6 cups vegetable or chicken stock (preferably homemade–I use chicken stock and I add some dry white wine to mine)
salt to taste
1/4 teaspoon cayenne pepper (adjust to however spicy you want your soup to be)
3/4 cup chopped cilantro

In a large saucepan, saute the onions and garlic in 3 tablespoons of oil for 5 minutes, until limp, then add the last tablespoon of oil and the potatoes and stir-fry for a minute. Add the stock, cover, and simmer for 45 minutes, until the potatoes are mushy. Remove from heat and puree (preferably not in the blender–I use a ricer but you could use a food processor, too). Return the soup to the pot, season with salt and cayenne, and stir in the chopped cilantro. Cover and refrigerate for 24 hours. You can serve the soup cold–or reheat by slowly bringing it to a simmer.