Cook potatoes in boiling water to cover in a Dutch oven 1 hour or until tender; drain. Peel potatoes, and discard skins.
Mash potatoes with a potato masher. Stir in butter until melted. Stir in eggs and next 11 ingredients, blending well. Spoon about 2 tablespoons mixture into each tart shell.
Bake at 350° for 45 minutes or until set. Store in an airtight container in freezer, if desired. Serve tartlets with whipped cream.
* 2 unbaked 9-inch pastry shells may be substituted. Spoon potato mixture evenly into pastry shells; bake as directed.