Pierogi Mini Taco Boats™

Scrub and peel potatoes. Cut into large pieces. In 2-quart saucepan, heat 1 inch water (salted, if desired) to boiling; add potatoes. Cover, and heat to boiling; reduce heat to medium-low. Cook potatoes 20 to 25 minutes or until tender; drain. Shake saucepan gently over low heat to dry potatoes. Meanwhile, in 10-inch skillet, heat 1 tablespoon of the butter over medium heat. Add onions and 1/4 teaspoon of the salt. Cook 10 to 15 minutes, stirring frequently, until golden brown. Transfer 1/4 cup of the onions to cutting board; chop finely. Set aside. In medium bowl, mash potatoes until no large lumps remain. Stir in milk, 1/4 cup of the cheese, remaining 1/4 teaspoon salt and the pepper. Stir in finely chopped onions. Heat oven to 325 °F. Brush insides of boats with remaining melted butter; place on ungreased cookie sheet. Bake 6 minutes. Spoon potato mixture evenly into warmed boats. If potato mixture has cooled off, place filled boats back in oven about 5 minutes or until heated through. Top with remaining onions, cheese and small dollop sour cream. Serve warm.