1 head celery, stalks chopped, leaves reserved
1 large waxy potato, chopped
1 medium onion, chopped
½ cup (1 stick) unsalted butter
3 cups low-sodium chicken broth
¼ cup fresh dill
½ cup heavy cream
Flaky sea salt (such as Maldon) and olive oil (for serving)
Combine celery, potato, onion, and butter in a medium saucepan over medium heat; season with kosher salt.
Cook, stirring, until onion is tender, 8–10 minutes.
Add broth; simmer until potatoes are tender, 8–10 minutes.
Purée in a blender with dill; strain.
Stir in cream. Serve soup topped with celery leaves, sea salt, and oil.