SERVES6 to 8

INGREDIENTS


For the potato layer:
3 pounds russet potatoes (4 to 5 large), peeled and diced
2 teaspoons kosher salt, divided
1/2 cup whole or 2% milk
4 tablespoons unsalted butter
1 large egg yolk

For the filling:

1 teaspoon vegetable oil
1 1/2 pounds lean ground beef
1 teaspoon kosher salt
1 (10-ounce) bag frozen vegetable medley, such as carrots, peas, green beans, and corn
1/2 cup water
2 tablespoons all-purpose flour
2 tablespoons ketchup
1 teaspoon onion powder
1/2 teaspoon garlic power


EQUIPMENT
12-inch oven-safe skillet


Measuring cups and spoons
Chef's knife and cutting board
3- to 4-quart pot with lid


Spatula
Potato masher

INSTRUCTIONS

Heat the oven to 400°F. Arrange a rack in the middle of the oven and heat to 400°F. Meanwhile, cook the potatoes.
Boil the potatoes. Place the potatoes in a large (3- to 4-quart) pot. Cover with about 2 quarts of water, stir in 1 teaspoon of the salt, and bring to a boil over high heat. Reduce the heat to medium-low, cover, and simmer until the potatoes are tender, 15 to 18 minutes. Meanwhile, make the filling.

Brown the beef. Heat the oil in a large oven-safe skillet — 12-inch cast iron is best — over medium-high heat until shimmering. Add the beef and salt, breaking it into large chunks as you add it to the pan. Let the meat brown for 1 to 2 minutes undisturbed, then use a spatula to break up the chunks into smaller pieces. Cook, stirring occasionally, until browned, about 10 minutes total.

Add the vegetables and sauce ingredients. Add the vegetables, water, flour, ketchup, onion powder, and garlic powder. Cook, stirring occasionally, until simmering, 2 to 3 minutes. Remove from the heat. Don’t worry too much if the browned beef mixture looks a little soupy -- it will thicken in the oven.

Mash the potatoes with the butter, milk, and egg yolk. Drain the potatoes and return them to the now-empty pot. Add the milk, butter, and remaining 1 teaspoon salt and mash to desired consistency (for shepherd’s pie we like a pretty smooth mixture). Stir in the egg yolk.

Top beef mixture with the mashed potatoes. Use a large spoon to dollop the mashed potatoes over the beef. Use the spoon to smooth the potatoes into an even layer.

Bake for 30 minutes. Bake until the potatoes just begin to brown and the filling is bubbling, 25 to 30 minutes. Cool for 10 minutes to let the sauce thicken slightly before serving.

RECIPE NOTES


Storage: Refrigerate leftovers in an airtight container for up to 3 days.

Using a casserole dish: If you’d rather serve in a casserole dish or do not own an oven-safe skillet, transfer the filling mixture to a 3-quart casserole dish before topping with the potatoes.