Combine broth with salt to taste in an 8-quart pot over medium heat.
Add potato, celery, and leek. Bring to a boil and then reduce heat to low. Cover and cook until vegetables are tender, about 20 minutes.
Puree vegetables in a blender or use an immersion blender in the pot. If using a high speed blender, like a Vitamix, only blend on low (blending on high speed will make the soup gummy).
Return puree to pot. Place over medium heat.
Ladle into bowls. Top with a dollop of plant-based sour cream or yogurt, and chives. Serve immediately.
Instant Pot Directions
To make this in an Instant Pot, add potato, celery, leek, vegetable stock, and salt into the pot and cook on High pressure for 10 minutes and then do a Quick release. Then blend and serve with plant-based sour cream or yogurt, and chives.