Preheat oven to 425°.
Bake potatoes at 425° for 1 hour and 10 minutes or until tender; cool slightly. Cut each potato in half lengthwise, and scoop out pulp. Discard skins.
Place potatoes and remaining ingredients in a small saucepan; mash to desired consistency. Cook over low heat 2 minutes or until thoroughly heated. Garnish with thyme, if desired.