The best lasagne

Heat the olive oil in the largest casserole dish you have, add the celery and onion and cook over a medium heat for 5 minutes, stirring often. Add the carrots, then sauté the vegetables for 10-15 minutes more, or until softened and reduced down.

Crumble the pork and beef mince into the pan and stir, breaking up any large chunks with a spoon, until browned all over. Pour in the 500ml milk, bring to a simmer, and leave to reduce for 20 minutes, stirring a couple of times during the process.

Once the milk has reduced by ½ and the liquid in the pan is more like water than milk, add the wine, stock cube and tomatoes. Stir well, then pop in the rosemary, cover and simmer on a low heat for 2 hours. The longer you simmer, the more intense and complex the flavour will be. If still liquidy after 90 minutes, remove the lid for the last 30 minutes. You could also do this by putting the pan into a preheated oven at 200ºC, gas mark 6. The liquid will reduce down almost entirely, with just a small amount in the bottom. If it looks too dry, add a splash of water or stock.

For the béchamel, melt the butter in a medium saucepan, then add the flour and whisk to a thick paste. Cook for 1 minute, whisking all the time, then begin to add the 800ml milk, a splash at a time. The mixture will thicken and become smooth. Stir in the nutmeg and ½ the cheese. Set aside, until ready to assemble.

Preheat the oven to 200ºC, gas mark 6. Take a large oven dish, about 33x23cm and 5cm deep, and work out how many sheets of lasagne you need to create a layer (you might have to break a few sheets in ½ to cover it all). Begin by layering in ¼ of your ragù, then top with a layer of pasta. Spread it with a layer of béchamel, then repeat 3 more times, using 4 layers of pasta and all the ragù.

Spread the remaining béchamel over the top of the final layer of pasta. Scatter with the mozzarella and remaining cheese. Brush the sage with a little oil and add to the top. Bake for 30-40 minutes, or until a knife cuts through the layers with little resistance. Allow to stand for 15 minutes (if you cut any sooner, the layers won’t hold together) before slicing and serving.