Start by washing and slicing the leeks, ensuring you use only the white and light green parts for a milder flavor. Peel and dice the Yukon Gold potatoes and carrots into bite-sized pieces. Chop the fresh dill, and cut the salmon fillet into uniform chunks.

In a large, heavy-bottomed pot, melt 2 tablespoons of butter over medium heat. Once the butter begins to bubble, add the finely chopped shallots and minced garlic. Sauté for about 4–5 minutes until softened and fragrant. Pour in ¼ cup of dry white wine to deglaze if using.

Stir in the diced carrots, celery, and potatoes, along with a bay leaf. Sprinkle 1 tablespoon of all-purpose flour over the vegetables, stirring for about a minute to coat. Gradually pour in 4 cups of fish stock, stirring continuously until combined, and bring to a gentle boil.

Reduce heat to low and let the soup simmer uncovered for 15–20 minutes until potatoes are tender. Stir occasionally to prevent boiling too vigorously.

Gently fold the salmon chunks into the soup, cooking for another 5–7 minutes until the fish is opaque and flakes easily with a fork.

Reduce heat to low and stir in 1½ cups of heavy cream and chopped dill, saving some for garnish. Season with salt, pepper, and 1 tablespoon of lemon juice. Avoid boiling after adding cream to maintain texture.

Ladle the soup into warm bowls, garnishing with reserved dill. Serve with crusty rye bread or sourdough.