Answer: If you said Vichyssoise, you were partly right - but given the temperature is close to 60 - a little chilly, it would be Potage Parmentier, basically, which is warm vichyssoise with a little extra butter. The only recipe I found was this, but I was horrified it called for garlic.
My recipe goes back to Le Bocage, I think - it's possible I changed it over the years. Actually, it's VERY possible:)
You will need:
2 cups clean leek whites, sliced and washed
2 tablespoons unsalted butter
1 cup water
2 cups light chicken stock
1/2 teaspoon tarragon (my favorite) or dill (dried)
1 teaspoon thyme (dried)
2 cups washed small potatoes, sliced or quartered
kosher salt and pepper to taste
1 cup heavy cream
1 last tablespoon unsalted butter, after pureeing
1 tablespoon fresh chives, minced, from the garden for garnish
Saute the leeks in the butter for 15 minutes in a large saucepan, then add the water, chicken stock, potatoes, thyme and tarragon or dill and cook until the potatoes are soft. Make sure the mixture has enough liquid, not enough liquid and it will scorch.
Remove from heat and puree with a stick processor, or a food processor, then add the cream and butter and puree one more time.
Pour or ladle into bowls and top with your lovely fresh chives, serve warm with warm bread and butter and a nice little salad.