Place potatoes in large saucepan; add enough water to cover. Add 1/2 teaspoon of the salt. Bring to a boil. Reduce heat to medium-low; cover loosely and boil gently for 15 to 20 minutes or until potatoes break apart easily when pierced with fork. Drain well.
Mash potatoes with potato masher. Add butter, pepper and remaining 1/2 teaspoon salt; continue mashing, gradually adding enough milk for desired consistency.