1 T unsalted butter
1 T vegetable oil
1 cup sliced leek, white part only
1 shallot, minced (or scallion, white part only, or white onion)
4 cups stock or water
10 ounces lettuces
3 medium potatoes, diced (2-1/2 cups)
salt and pepper, to taste
1 T fresh dill (or 1 t dried)
3 T half-and-half (or whole milk, or cream)

1. Melt butter in a Dutch oven over medium heat. Add the oil, leek and shallot; toss to coat. Cook two minutes until the leeks are softened.

2. Add the stock, lettuces and potatoes. Cook, partially covered, until potatoes are tender, about 15 minutes. Season with salt and pepper to taste, then stir in the dill. Cool, then refrigerate at least 3 hours.

3. Before serving, stir in the half-and-half.