Chilled Tomatillo Soup

2 tsp olive oil
1 onion, chopped
1 lb tomatillos, husked, rinsed, and quartered
2 galric cloves, minced
1 jalapeno pepper, seeded and chopped
3 cups vegetable stock
1 tsp cumin
2 Tbsp cilantro
1 cup buttermilk
salt and pepper
Heat olive oil in saucepan over medium heat. Add the onion and cook until translucent- about 10 minutes.
Add tomatillos, garlic, and jalapeno and cook for 5 minutes. Raise the heat to medium-high, add the stock, cumin, and cilantro and cook 10 minutes more. Remove from heat and cool.
Use an immersion blender or blend the soup in a food processor. Add the buttermilk, salt and pepper. Chill before serving.