Sweet Potato and Lean Beef Cottage Pie

A lightly browned cheese crust gives way to crumbled beef scented with thyme and bound with a short tomato-rich pan sauce. The sweet potato mash stays soft and smooth, its natural sweetness balanced by pepper and garlic.

Instructions

1. Boil the sweet potatoes

   Heat the oven to 200°C / 400°F. Peel the sweet potatoes, cut them into even chunks and add them to a pan of salted boiling water. Cook for 15–20 minutes, until a knife slips in easily.

2. Mash the sweet potatoes

   Drain the sweet potatoes thoroughly, then mash while hot with the milk and butter. Season with salt and pepper, working just until the mash is smooth and soft.

3. Soften the onion and garlic

   Peel and finely chop the onion and garlic. Heat the oil in a frying pan, add them and cook for 3–4 minutes, until the onion turns translucent without browning.

4. Cook and season the beef

   Add the minced beef and thyme sprig. Cook for 6–8 minutes, stirring and breaking the meat into small pieces with a spatula. Stir in the tomato paste, season with salt and pepper, and keep the mixture moist but not wet.

5. Assemble and bake the pie

   Remove the thyme sprig and spread the beef in a baking dish. Cover with the mash, smoothing it without pressing it down, then scatter over the grated cheese. Bake at 200°C / 400°F for 15–20 minutes, until the cheese is melted and lightly browned.

Chef's tips

• Let the sweet potatoes steam off after draining before adding the milk; excess moisture can loosen the beef layer.
• Cook the onion until translucent before adding the beef. It softens fully without scorching as the meat cooks.
• Spread the mash without pressing it down. A looser layer heats evenly and stays soft beneath the cheese.

Storage

Keep covered in the fridge for up to 3 days. Reheat in a 160°C / 320°F oven until hot in the centre. Freeze in portions for up to 2 months.