1/4 cup all purpose flour
1 chopped onion
1 chopped green bell pepper
1/2 chopped red bell pepper
3/4 cup finely chopped celery
1 heaping tablespoon minced garlic
1 tablespoon chopped fresh thyme
2 tablespoons tomato paste
2 cups vegetable stock
To make the soup, heat the butter in a stockpot over medium-high heat. Add the onions, garlic, and a bit of salt. Saute for a few minutes, or until the onions start to get translucent. Stir in the potatoes and squash and cook for another 7-10 minutes, or until the squash starts to soften up. Stir in 3 1/2 cups of the stock (most of it) - the stock should just barely cover the vegetables. Bring to a boil. Reduce heat to a simmer and cook until the potatoes are tender, roughly another 25 minutes. Remove the soup from heat, puree completely with a hand blender, then stir in the buttermilk. If you need to thin the soup out with a bit more stock, you can do so. Taste and add more salt if needed. Serve each bowl topped with plenty of the cumin butter, and a sprinkling of chives.
Since the initial making of this soup, I couldn't get enough of it and made another batch. It hold up really nicely in the fridge, which makes it a great thing to prepare ahead of time if needed.