1. Arrange potatoes in a vegetable steamer over boiling water. Cover and steam 15 to 20 minutes or until tender. Remove from steamer; let cool.
2. Scoop out centers of potatoes with a melon-ball scoop or small spoon; set aside potato shells.
3. Mash potato pulp at medium speed of an electric mixer until smooth. Stir in sour cream and remaining ingredients. Spoon or pipe evenly into potato shells, using a decorating bag fitted with a large round tip.
4. Place stuffed potatoes on a baking sheet. Bake at 425° for 10 to 15 minutes or until thoroughly heated.