Cut the cheese into 6 wedges. Carefully remove the rind from the cheese, discarding the rind. Chop the cheese and let it stand at room temperature while the potatoes cook.
Place the potatoes in a large Dutch oven. Cover them with water and bring to a boil. Reduce heat; simmer 12 minutes or until tender.
Drain in a colander and return the potatoes to the pan. Add the cheese, milk, salt and ¾ teaspoon pepper; mash with a potato masher until smooth.
Garnish with chives and additional pepper, if desired.