1In a Dutch oven or heavy pot over medium heat, melt the butter (or warm the oil). Cook the leeks with a sprinkle of salt until tender, about 5 minutes.
2Add the potatoes, broth, and 1 teaspoon salt; stir to mix well. Bring to a boil, partially cover, reduce the heat to low, and simmer until the potatoes are tender, about 20 minutes.
3Depending on how smooth or chunky you like your soup, you can purée it in a blender (very smooth), puree it with an immersion blender (smooth), or use a potato masher to mash the potatoes until slightly chunky.
4Taste and adjust the seasoning with salt and pepper. Serve in warmed bowls.
From south of the border comes this spicy and hearty soup ladled over crisp tortilla strips and grated cheddar. The soup is chunky with chicken and avocado, but it's the tortillas that give it a slight thickness and a special flavor.