- 3 tablespoons butter
- 2 leeks (white and pale green parts only), sliced (about 2 cups)
- 1 small onion, chopped
- 4 garlic cloves, sliced
- 2 tablespoons water
- 1/2 pound red-skinned potatoes, unpeeled, cut into 1/2-inch pieces
- 4 cups low-salt chicken broth or vegetable broth
- 2 teaspoons chopped fresh tarragon
- 1/2 cup whipping cream
- 1/2 cup plain whole yogurt
- Melt butter in heavy large pot over medium heat. Add leeks, onion, garlic, and 2 tablespoons water. Cook until leeks are just golden, about 10 minutes. Add potatoes and broth; bring to boil. Reduce heat to low and simmer until potatoes are tender, about 10 minutes. Mix in tarragon. (Can be made 1 day ahead. Cool slightly. Cover and refrigerate. Rewarm before continuing.) Stir in cream and yogurt. Season soup to taste with salt and pepper.