Created by KittenCal on October 1, 2014
Step 1: Cut potatoes into 2-inch cubes; put into a large saucepan. Add water to cover the potatoes. Heat over high to a rolling boil; reduce heat to a gentle rolling boil. Cook until the potatoes are fork-tender, about 15 minutes. Drain off the water. Working in the pan, mash the potatoes with the half-and-half, egg yolk, salt and pepper until smooth. Let stand until cool enough to handle, then stir in the chives.
Step 2: Put the breadcrumbs into a shallow dish.
Step 3: Use your hands to shape the potato mixture into small football shapes, using about 3 tablespoonfuls per piece. Roll in the crumbs to coat on all sides. Set on a wire rack. Refrigerate for 2 or more hours.
Step 4: Heat a fair amount of oil (with the butter) in a large skillet over medium-high heat until hot but not smoking. Add the croquettes in a single uncrowded layer. Fry, turning gently, until golden and crisp on all sides, about 5 minutes. Serve hot.