Tarragon Yogurt Sauce

2 tablespoons olive oil
1/2 cup finely chopped onion
1 1/2 teaspoon finely minced garlic
2 tablespoons cornstarch
1 cup chicken stock
1/2 teaspoon salt
1/2 teaspoon freshly ground black pepper
1 1/2 tablespoons dried tarragon
1 cup plain fresh yogurt

Heat olive oil in a pan over medium heat, and saute the onion and garlic until translucent. Stir 2 tablespoons cornstarch into 2 tablespoons chicken stock to make a slurry. Add the remaining chicken stock to the onion/garlic mixture and bring to a simmer. Add the slurry and bring to a boil. when the mixture comes to a boil, remove from the heat. Add the salt, pepper, tarragon and yogurt, and heat until warmed through, about 1 minute. Do not boil.