Place potatoes in 3-quart saucepan; add enough water (salted if desired) to cover. Cover and heat to boiling; reduce heat. Simmer about 20 minutes or until potatoes are tender; drain. Shake potatoes in saucepan over low heat to dry.
Add butter, buttermilk, cheese, salt and pepper to potatoes. Lightly mash with fork or back of spoon keeping some larger pieces of potatoes.