Preheat the oven to 325°F.
Place the peeled shallots in a small sauce pan with 1 teaspoon of the olive oil.
Cover and place in the oven. Roast for 30 minutes.
Remove and place in a blender with the remaining 3 teaspoons olive oil, tarragon, vegetable stock, vinegar and salt.
Puree until smooth.
Chill.
