Classic Shepherd's Pie (British Lamb Mince Pie with Buttery Cheddar Mashed Potato Topping)

Shepherd's pie is the great British comfort dish: a deep layer of minced lamb cooked slowly with onion, carrot, celery and thyme in a glossy gravy, topped with a thick blanket of mashed potato and baked until the ridges turn crisp and golden. One point of terminology before we start: made with lamb it is a shepherd's pie (shepherds keep sheep), and the same dish made with beef is a cottage pie. Either way it is exactly what you want on a cold, dark autumn evening, and it feeds six generously from one baking dish.

Three things separate a good shepherd's pie from a grey, watery one. First, the lamb is browned hard in batches so it develops real color and flavor before the vegetables go in, and the excess fat is drained so the filling isn't greasy. Second, the filling is simmered with tomato paste, Worcestershire sauce and a splash of red wine until it is thick enough to hold a spoon trail; a loose filling bubbles up through the potato and turns the top soggy. Third, the mash is made with floury potatoes, plenty of butter and warm milk, kept firm enough to hold fork marks, and spread over a filling that has cooled for a few minutes so it sits on top rather than sinking in.

The whole thing can be assembled a day ahead and baked when you need it, which makes it one of the most useful make-ahead dinners for a busy week or a relaxed Sunday.

Ingredients

For the lamb filling

• 1 tablespoon olive oil
• 750 g (1.65 lb) minced lamb, ideally about 15 to 20 percent fat
• 1 large onion, finely chopped
• 2 medium carrots, about 200 g (7 oz), cut into 1 cm (1/2-inch) dice
• 2 celery stalks, finely diced
• 3 garlic cloves, finely chopped
• 2 tablespoons tomato paste
• 1 tablespoon all-purpose flour
• 150 ml (2/3 cup) dry red wine, or extra stock
• 400 ml (1 2/3 cups) lamb or beef stock
• 2 tablespoons Worcestershire sauce
• 1 teaspoon dried thyme, or 3 sprigs fresh thyme
• 1 bay leaf
• 150 g (1 cup) frozen peas
• Salt and freshly ground black pepper

For the mashed potato topping

• 1.2 kg (2.6 lb) floury potatoes such as Russet, Maris Piper or King Edward, peeled and cut into 4 cm (1 1/2-inch) chunks
• 75 g (5 tablespoons) unsalted butter
• 100 ml (scant 1/2 cup) whole milk, warmed
• 75 g (3/4 cup) grated mature cheddar, optional
• A pinch of ground nutmeg, optional

Instructions

1. Start the potatoes. Put the chunks in a large pot, cover with cold water by 3 cm (1 inch), add a big pinch of salt and bring to a boil. Simmer for 15 to 18 minutes, until a knife slides in with no resistance. Drain well, return them to the hot pan and let them steam-dry over the lowest heat for 2 minutes so the mash isn't wet.
2. Mash the potatoes until smooth, then beat in the butter, the warm milk, a good pinch of salt, pepper and the nutmeg if using. The mash should be firm enough to hold its shape on a spoon, not runny; add the milk gradually and stop when it is smooth but stiff. Cover and set aside.
3. While the potatoes cook, heat the olive oil in a large, wide pan over high heat. Add half the lamb and leave it alone for 2 minutes before breaking it up, then cook for 5 to 6 minutes, until deeply browned with crisp edges. Transfer to a bowl and repeat with the rest. Tip off all but about 1 tablespoon of the fat.
4. Reduce the heat to medium and add the onion, carrot, celery and a pinch of salt to the same pan. Cook for 8 to 10 minutes, stirring occasionally, until softened and lightly golden at the edges. Stir in the garlic and cook for 1 minute, then add the tomato paste and cook for another minute, until it darkens slightly.
5. Return the lamb to the pan, sprinkle over the flour and stir for 1 minute to coat. Pour in the red wine and let it bubble for 2 minutes, scraping the bottom of the pan, until it has almost evaporated.
6. Add the stock, Worcestershire sauce, thyme and bay leaf. Bring to a simmer, then cook uncovered over medium-low heat for 20 to 25 minutes, stirring now and then, until the gravy is thick and glossy and a spoon dragged through it leaves a trail that slowly fills. Stir in the peas, discard the bay leaf and season generously with salt and pepper.
7. Heat the oven to 200°C (400°F). Spoon the filling into a 2-liter (2-quart) baking dish, about 23 x 30 cm (9 x 12 inches), and let it cool for 5 minutes so the surface firms up slightly.
8. Dollop the mash over the filling in spoonfuls, starting at the edges and working inward, then gently spread it to the sides of the dish to seal the filling in. Drag a fork across the top to make ridges, which will crisp up in the oven, and scatter over the cheddar if using.
9. Bake for 25 to 30 minutes, until the top is golden and the gravy is bubbling at the edges. For a darker, crisper top, finish under a hot broiler for 2 to 3 minutes. Let it rest for 10 minutes before serving so the filling sets enough to cut clean portions.

Tips

• Substitutions: use minced beef and you have a cottage pie, cooked exactly the same way. Half lamb, half beef also works well and is a little milder. Skip the wine and use 150 ml extra stock plus 1 teaspoon balsamic vinegar for the acidity. Worcestershire sauce can be swapped for 1 tablespoon soy sauce plus 1 teaspoon brown sugar. For a dairy-light mash, use olive oil and the potato cooking water in place of butter and milk.
• Make ahead: assemble the pie completely, cool, cover and refrigerate for up to 2 days, then bake from cold at 190°C (375°F) for 40 to 45 minutes. It also freezes well for up to 3 months, either whole or in portions; thaw overnight in the fridge before baking. Leftovers keep for 3 days and reheat best in the oven at 180°C (350°F) for 20 minutes, covered with foil for the first 10.
• What to serve with it: buttered peas or green beans, braised red cabbage, or simply a pile of steamed greens with a squeeze of lemon. A few pickled onions or a spoon of brown sauce on the side is very British. A glass of red wine or a pint of ale suits it perfectly.
• Choose the right potato. Floury varieties break down into a light, fluffy mash that browns beautifully. Waxy salad potatoes turn gluey when mashed and stay pale in the oven.
• If the filling looks thin after simmering, keep cooking it; a runny filling is the most common reason a shepherd's pie collapses when served. Conversely, if it gets too thick and dry, loosen with a splash of stock.
• Ridging the mash with a fork isn't just for looks: the peaks brown and crisp while the valleys stay soft, giving you two textures in every spoonful. Brushing the top with a little melted butter before baking makes it even more golden.

Nutrition

Nutrition information is an estimate only: about 700 kcal, 30 g protein, 42 g fat, 42 g carbohydrate per serving.