Heat olive oil in a heavy-bottomed pot over medium-high heat.
Add the potatoes and leeks, season with salt and pepper, and cook for 5-8 minutes to sweat the leeks.
Add 6 cups of water and 4 teaspoons of Better Than Bouillon vegetable base, and bring to a simmer.
Simmer the potatoes and leeks for 30-40 minutes, until the potatoes are very tender.
Add the kale or other greens and cook for a few minutes until wilted.
Remove from heat and stir in ¼ cup of sour cream and 1 teaspoon of vinegar.
Serve the soup topped with more sour cream, scallions, and a generous amount of dill.
