2 tablespoons minced parsley
Warm butter, leeks, and salt in a large pot or Dutch oven over medium-high heat. Cook until sizzling, stirring frequently, then cover and reduce heat to low. Cook for 10 minutes more, or until leeks have softened.
Add potatoes and stir, then pour in vegetable stock until leeks and potatoes are just covered. Bring to a simmer, adding salt and pepper to taste. Increase heat to medium and simmer until potatoes are soft, 25 to 30 minutes. Add more stock as needed to keep potatoes and leeks covered.
Once potatoes are soft and break apart easily, use an immersion blender or a food processor to puree until smooth. (Cool slightly before transferring to a blender or food processor. Return the blended soup to the pot.)
To the same pot over medium heat, add broccoli and cook until slightly tender, 5 minutes.
Add raclette and stir until completely melted. Adjust seasoning as needed.