You can't whack this together

I've tried making shepherd's pie with all sorts of cuts of lamb and a lot of them turn out tasting of very little. Whatever lamb mince is made from it's definitely not the part with the flavour. So this recipe is the result of a lot of experimentation and a fair amount of disappointment. This could equally be called a hotpot recipe - I'll leave it to culinary philosophers to debate the difference. I prefer the sliced potato top as you get texture and flavour that's practically impossible to achieve with mash.

Two warnings:

This takes a long time. You can't whack this together when you get home from work, it's a weekend/lazy day recipe that rewards long slow cooking.

It makes deliberate use of a fatty cut of meat and the fat is an integral part of the recipe. The potatoes are almost confit and won't work without it. If you, or someone you're cooking for, has a panic attack at the sight or taste of anything other than lean (flavourless) meat then don't attempt this.

You will need:

A whole shoulder of lamb, boned (keep the bones), cut into 3-4 cm chunks. Don't trim the fat or skin off.
Two leeks, finely sliced and thoroughly rinsed.
About 300g of carrots, cut into 2-3cm chunks.
Four banana shallots, peeled and coarsely diced.
Four cloves of garlic, peeled and flattened with the blade of a knife.
Three large sticks of celery, scrubbed and coarsely diced.
One litre of good quality lamb stock.
About 300g of celeriac, peeled and thinly sliced.
About 300g of floury potatoes, thinly sliced.
A drizzle of olive oil.
50g of butter, diced into small cubes.
Lots of salt & pepper.

Pre heat your oven to 200C.

Put the lamb bones, leeks, carrots, shallots, garlic and celery into a roasting pan, season and drizzle with the oil and put into the oven.

While the veggies are in the oven brown the lamb in a frying pan in small batches. Browning adds flavour so don't skimp on this bit. Blackening also adds flavour but not the kind you're looking for so don't over-do it. Keep checking the veggies and give them a stir if they're starting to colour. Again - brown bits are good, black bits are bad.

Once the meat is browned and the veggies have had a chance to get some colour add the meat to the roasting pan, season again and pour over half of the lamb stock. Cover the pan tightly with tin foil, return to the oven and turn the temperature down to 130C.

This will need about 3-4 hours for the meat to cook through, the chewy bits to render down and the flavour to develop.

Once the meat is cooked take the pan from the oven, remove the bones and layer the potato and celeriac on top in alternating layers, finishing with a layer of potato. Season, dot with the butter and pour over the remaining stock. Return to the oven uncovered and raise the temperature to 160C.

This bit takes about an hour or two depending on how you prefer the finished article. As the potatoes cook press them down gently so the stock flows up to cover them. As the stock is absorbed the lamb fat will confit the potatoes. It's up to you how long this bit goes on for - I'm a fan of crispy potatoes and not so much gravy so I tend to leave it for about an hour and a half.

This will feed six hungry people with leftovers.