Cottage pie is not a dumping ground for grey mince. It is a browned filling, a savoury gravy, and mash that is not soup. Lean mince makes that job stricter because there is less fat to hide a timid pan. Lean Beef Mince 400g is one pie for four modest plates. Lean beef mince in the 5 x 400g pack is three pies or two pies and a bolognese, which is how a family actually uses mince if they are not pretending one 400g tray is a fortnight.
Brown the mince like you mean it
Use a wide pan. If the mince sits in a heap it boils in its own water and you will never get colour. 400g of lean mince, a little oil, high heat, break it up and leave it alone for a minute at a time. Salt it. Add onion, carrot, celery if you have them. Tomato puree cooked out for a minute. A splash of Worcestershire, stock to loosen, not to swim. Simmer 20 minutes until it looks like a filling, not a soup. Taste for salt. Lean mince is blunt if you under-season; it is not bland if you cook it properly.
Spread the filling in a dish and let it stop bubbling before the mash goes on, or the mash sinks. Mash is potato, butter, a splash of milk, salt. Pipe or fork the top. 190°C for 25 to 30 minutes until the ridges catch. Rest 10 minutes so you can plate it instead of pouring it.
Pack size and leftovers
Fresh Lean Beef Mince - 5 x 400g lets you freeze the extra 400g packs unopened. Do not freeze a finished pie unless you like soggy mash; freeze the filling in a tub and mash it fresh. Shop minced beef if you want a slightly richer mince for a colder night — lean is the weekday pie, not a law. Leftover pie reheats covered at 180°C. It is Thursday food, and it should taste like Thursday food done well, not like a can.
What not to do
Do not hide under-browned mince under cheese and call it chef-y. Do not use a tiny pan. Do not skip the rest. Do not make it with watery leftover stew and expect a pie. Cottage pie is a mince dish with a lid of potato. Treat the mince as the point, buy a pack you will actually brown in one go, and it will feed people without a speech about protein.