How to Make It
Heat a stockpot over medium-high heat. Add oil and next 4 ingredients; cook 2 minutes. Add herbs and stock; cover and cook 4 minutes.
Remove from heat; transfer two-thirds of mixture to a blender. Add potatoes and half-and-half. Remove center piece of lid; secure lid on blender. Cover opening with a towel; blend until smooth.
Return pureed soup to pan over medium heat. Stir in vinegar, salt, pepper, and chicken; cook 2 minutes. Top soup with yogurt.