Why you’ll love this recipe

  • The filling and topping make a complete main dish.
  • Fork ridges encourage a lightly browned surface.

Ingredient notes

  • Ground beef makes a cottage-pie variation.
  • The listed cooking time allows the potato and meat preparations to overlap.

Equipment you’ll need

  • Saucepan
  • Large skillet
  • 2 1/2-quart baking dish
  • Potato masher

Helpful cooking tips

  • Let potatoes steam dry briefly after draining.
  • Keep the filling thick enough to support the topping.

Make it your own

Variations

  • Mix 1/2 cup grated cheddar into the mashed potatoes.

Substitutions

  • Use ground beef instead of lamb and cook it to 160°F / 71°C.

What to serve with it

  • Serve with green beans or a sharp-dressed salad.

Storage, freezing & reheating

In the refrigerator

Divide leftovers into shallow containers and refrigerate within 2 hours (within 1 hour if above 90°F / 32°C). Keep at 40°F / 4°C or colder and use within 3–4 days.

In the freezer

Freeze cooled portions in sealed freezer containers for up to 2 months for best quality. Thaw overnight in the refrigerator.

To reheat

Reheat a single portion in the microwave, loosely covered, stirring or turning halfway through. Heat to 165°F / 74°C throughout; add a spoonful of water if needed.

Frequently asked questions

Can I use leftover mashed potatoes?

Yes. Use about 4 cups, loosen with a little milk if stiff, and heat the finished casserole to 165°F / 74°C.