Peel and cube 1 lb Yukon Gold potatoes; finely chop onion and mince garlic. Keep sizes even for consistent cooking.

Melt 2 tbsp butter in a pot over medium heat; cook onions until translucent (about 5 minutes), stirring occasionally, then add garlic until fragrant.

Pour in 4 cups broth, bring to a gentle simmer. Cook until potatoes are fork-tender, about 15–20 minutes, with gentle bubbles.

Cut 1 lb salmon into bite-sized chunks; gently stir into the simmering soup. Cook until opaque and flaky, about 5–7 minutes.

Lower heat and whisk in 1 cup heavy cream and 1 tbsp butter. Heat through without boiling, creating a silky, velvety broth.

Squeeze juice from half a lemon, season with salt and pepper to taste. Ladle into bowls, sprinkle fresh dill, and serve warm.