Prepare the stock by pouring it into a large pot and bringing it to a gentle simmer over medium heat for 5–8 minutes.

If using, chop the onion finely and sauté it in a skillet with olive oil for 3–5 minutes until soft. Transfer to the simmering stock.

Peel and dice potatoes into 1-inch chunks, add them to the stock, raise the heat to boil, then simmer for 15–20 minutes until tender.

Blend the soup until silky smooth using an immersion blender or a regular blender.

Stir in the chopped dill and cream, heating on low for 2–3 minutes.

Season with salt and pepper, serve warm, and garnish with dill if desired.