3 large baking potatoes, peeled and diced
The white and pale green parts of 2 leeks: trimmed, washed, and chopped
1 qt chicken or veggie stock
2 tbsp butter
Salt and pepper to taste
In a large, heavy-bottomed pot over medium heat, melt the butter.
Add chopped leeks and "sweat" for ten minutes, stirring often, until softened.
Add potatoes, broth, salt and pepper. Bring to a boil.
Reduce heat to low and simmer, uncovered, for about twenty minutes, until potatoes are tender.
Blend in a food processor or with an immersion blender. (Blenders are discouraged for potatoes: they turn gummy.)
Return blended soup to pot and season to taste.