Peel, wash and roughly dice the potatoes. Cover and cook in the broth for about 15 minutes. Clean and wash the leek and cut into rings. Peel and chop the garlic, add to the potatoes after 10 minutes. Remove about 4 tablespoons of potato cubes from the broth. Puree the rest of the potatoes and garlic in the stock. Add the leek and peas to the soup. Let everything simmer for another 5 - 8 minutes.
Drizzle the crab meat with lemon juice and let it steep briefly.
In the meantime, add the processed cheese to the soup and let it melt while stirring. Season the soup with salt and pepper. Briefly heat the crabs and remaining potato cubes in it.