INGREDIENTS
* 1 tablespoon butter
* 1 teaspoon oil
* 1/2 cup minced red onion, shallot, or yellow onion
* Pinch each sugar and salt (1/8 teaspoon)
* 2 cloves garlic, minced
* 1/2 teaspoon dried tarragon
* 1/4 teaspoon thyme
* 1/4 teaspoon rosemary
* 1 tablespoon sherry vinegar
* 1/2 cup plain Greek yogurt
* 1/2 teaspoon salt
* 1/4 teaspoon pepper
* 1 tablespoon fresh minced parsley