Ingredients Meat & Poultry Beef Recipes Ground Beef Recipes Stuffed Meatloaf 3.5 (38) 1 Review By Martha Stewart Test Kitchen Martha Stewart Test Kitchen The recipes developed by our test kitchen team have undergone a rigorous process of development and testing, ensuring that every element is optimal, from ingredient amounts to method and cooking time. This process includes triple-testing recipes to ensure they meet our high standards. The many stellar cooks and food editors who have been part of our team include Sarah Carey, Lucinda Scala Quinn, Jennifer Aaronson, Shira Bocar, Anna Kovel, Greg Lofts, Riley Wofford, Lauren Tyrell, and Lindsay Leopold. Editorial Guidelines Updated on September 28, 2016 Print Rate It Share Share Tweet Pin Email Servings: 4 Create two delicious dishes in one. Reinvent the classic duo by baking fluffy mashed potatoes into the middle of meatloaf. Ingredients 1 pound Yukon gold potatoes, peeled and cut into ½-inch pieces 8 tablespoons (1 stick) unsalted butter, softened ¼ cup heavy cream 2 ½ teaspoons salt ½ teaspoon freshly ground plus a pinch of pepper 2 pounds ground beef 1 medium onion, finely chopped 3 tablespoons Dijon mustard 1 large egg ¼ cup fresh bread crumbs ¼ cup plus 2 tablespoons ketchup Directions Preheat oven to 350 degrees. Place potatoes in a large saucepan; add enough cold water to cover by about 2 inches. Bring to a boil over medium-high heat. Cook until tender, about 20 minutes. Transfer to a colander, and drain; return potatoes to pan. Mash potatoes with a fork or potato masher until light and fluffy. Add butter, cream, 1/2 teaspoon salt, and a pinch of pepper; stir until combined, and set aside. Combine ground beef, onion, mustard, egg, breadcrumbs, 1/4 cup ketchup, 2 teaspoons salt, and 1/2 teaspoon pepper in a large bowl. Place half the mixture on a rimmed baking sheet, and form into an 11-by-6-inch loaf. Place 1 1/2 cups of mashed potatoes on top of meat mixture, leaving a 1-inch border. Place the remaining meat mixture on top; form into a loaf, encasing the potato mixture. Bake 30 minutes, then brush remaining 2 tablespoons ketchup over meat loaf. Continue baking meat loaf until firm to the touch, about 20 minutes more. Serve immediately. Rate it Print