If you’ve never had a Shepherd’s pie, this is the place to start. Enjoy a savory staple with a mashed potato topping and a succulent meaty base that is sure to be a hit with almost any crowd.
Technically, this is a cottage pie, because it uses beef instead of lamb, but it tastes like an instant classic and it is a nice introduction for beginner cooks or picky eaters.
Use a fork to fluff up the mashed potatoes just before they go into the oven to get that signature shepherd's pie texture on top. More surface area also means a crispier crust!
Shepherd's pie casserole 
Ingredients ¾ lb russet potatoes, peeled and diced
2 tablespoons whole milk
2 tablespoons unsalted butter
1 egg yolk
Salt and pepper to taste
1 tablespoon vegetable oil
½ yellow onion, diced
2 cloves garlic, diced
1 medium carrot, diced
1 rib celery, diced
¾lb ground beef
1 tablespoon tomato paste
¼ cup beef broth
¼ cup red wine
1 teaspoon Worcester sauce
½ cup frozen English peas
1 teaspoon each of rosemary, thyme, and sage
1 tablespoon corn starch
¼ cup grated parmesan cheese
Directions1. Place the potatoes in a medium pot and cover with cold water. Bring to a boil and cook 15 minutes. Drain and return to the pot along with the milk, butter, egg yolk, salt and pepper. Mash until everything is homogenous and smooth. Set aside.
2. Heat the oil in a large, deep pan over a medium heat. Add the onion and garlic and sweat until they begin to go translucent. Add the carrot and celery and continue to cook about 3 minutes, until beginning to soften.
3. Increase the heat to medium-high and add the beef, breaking it up with your spoon and stirring until it has completely browned. Add the tomato paste, beef broth, wine, Worcester sauce, peas and spices. Stir to combine and bring the mixture to a simmer. Reduce the heat to medium and cook for 30-45 minutes. Add corn starch if desired for extra thickness.
4. Preheat the oven to 350 degrees Fahrenheit.
5. Pour the beef mixture into the bottom of a heavy 8x8 inch casserole dish.
6. Spread the mashed potatoes evenly over the top. Top with the grated parmesan cheese.
7. Bake for 20-25 minutes, or until the top is golden brown and the edges are bubbling. Allow to cool 5 minutes before serving.
