Melt 2 tablespoons of unsalted butter in a large Dutch oven over medium heat. Add 1 diced onion and 2 sliced carrots, and sauté for about 5 minutes until translucent.

Stir in 1 teaspoon of salt, ½ teaspoon of white pepper, ½ teaspoon of allspice, and a pinch of nutmeg. Cook for around 1 minute until aromatic.

Pour in 6 cups of water and add 3 medium Yukon Gold potatoes. Bring to a boil, then simmer for about 12 minutes until the potatoes are fork-tender.

Gently stir in 1 cup of heavy cream, then add 1 pound of salmon. Cook gently for about 5 minutes until the salmon is opaque.

Remove from heat and stir in 1 tablespoon of lemon juice and a generous handful of chopped fresh dill. Let rest for a couple of minutes.

Ladle the soup into bowls and garnish with extra dill or lemon wedges before serving.