METHOD

Making the ragù:

Mise en place is your friend! Prep the following ingredients: 1) Dice the unsmoked pancetta into small cubes (around ½ cm). 2) Finely chop the sweet onion, carrots and celery stalks. 3) Thinly slice the garlic cloves. 4) Remove the rosemary leaves from their stems, leaving them whole. 5) Measure out the white wine. 6) Carefully pour the tinned tomatoes into a large bowl and crush the tomatoes with your hands. 7) Measure out the chicken stock. 8) Measure out the milk.
Cut the brisket joint into 8 equal-ish pieces. Pat dry and season with 2 tsp sea salt and ½ tsp freshly-ground black pepper. Use the brisket pieces to mop up the salt and pepper that falls onto the chopping board. It may look like a lot of salt, but trust me on it!
Heat 1 tbsp extra-virgin olive oil in a large Dutch oven over medium-high heat. Working in 2 batches, sear the brisket pieces, turning occasionally, until browned on all sides; this process should take around 5 minutes per batch. Once browned, transfer the brisket pieces to a plate or shallow bowl.
Wipe down the pot with some kitchen towel; you want to remove the oil and any loose burnt bits but leave the fond— the caramelized drippings of the brisket that are stuck to the bottom of the pot—behind (see photo below).
Turn the heat down to medium, add the pancetta and cook, stirring occasionally, until the fat has rendered out and the unsmoked pancetta is browned and beginning to crisp, 6 to 8 minutes.
Add the onion, carrots and celery stalks and cook, stirring occasionally, until nice and soft, 10 to 12 minutes.
Add the garlic and cook for 1 minute, stirring constantly. Add the fresh rosemary leaves and cook for another minute, stirring constantly.
Add the tomato purée and sundried tomato paste and cook, stirring constantly, until they begin to darken, 4 mins.
Turn the heat up to medium-high. Add the white wine and cook, stirring occasionally, until it is reduced by around ¾, around 15 minutes.
Add the tinned tomatoes, chicken stock and milk, return the meat (and its juices) to the pot and bring to a simmer. Reduce the heat to low and cover, leaving the lid slightly ajar. Simmer gently, stirring occasionally, until the meat is fall-apart tender, 4 ½ to 5 ½ hours.
Alternatively, you can bake the ragù: add the tinned tomatoes, chicken stock and milk, return the meat (and its juices) to the pot and bring to a simmer. Cover, leaving the lid slightly ajar, and bake at 150°C/fan 130°C until the meat is nice and tender, 5 to 6 hours. Don’t forget to preheat your oven beforehand!
Remove the pot from the heat. Transfer the beef to a large bowl, loosely cover with aluminium foil and allow to rest for 10 mins, then coarsely shred using 2 forks. Return the shredded beef to the sauce. Taste and season with sea salt and freshly-ground black pepper.

MAKE AHEAD: the ragù can be made up to 3 days ahead; cool, transfer to airtight containers and refrigerate. Alternatively, it can be stored in the freezer for up to 2 months; thaw completely before use.

Making the béchamel:

Gently bring the milk to a bare simmer in a large saucepan over medium heat. Once it begins to bubble, remove the saucepan from the heat.
Melt the butter in a large stockpot or saucepan over medium heat. Whisk in the flour and cook for 3 mins, whisking continuously.
Quickly but carefully whisk in the warm milk and increase the heat to medium-high. Bring to a simmer, whisking often. The béchamel will begin to thicken. Once it barely starts bubbling—a few small bubbles coming up to the surface—reduce the heat to medium-low and cook until thick and velvety-smooth, around 5 mins.
Remove from the heat and whisk in the Parmigiano Reggiano, 1 ½ tsp sea salt, ½ tsp freshly-ground black pepper and a pinch of nutmeg.

MAKE AHEAD: the béchamel can be prepared the day before; cool, cover and refrigerate. Gently reheat in a saucepan to loosen before use.

Assembling the lasagna:

Heat oven to 200°C/fan 180°C. Lightly oil a deep 35 cm x 25 cm baking dish.
Spread 2 ½ cups ragù onto the base of the dish. Cover with a single layer of lasagna sheets; you will likely need to cut some of the sheets to fill all the gaps. Spoon 1 ¼ cup béchamel over the lasagna sheets, spreading it in a thin, even layer with a spatula.
Repeat the layers—ragù, lasagna sheets, béchamel—until you get to the top of the dish; 4 to 6 layers depending on how deep your dish is. Fill the dish right up to the top; the top pasta-béchamel layer will get nice and crunchy when baked.
Place the lasagna on an oven tray (to catch spills) and bake for 45 mins or until pasta is cooked through and the top is browned and crisp around the edges. Let it rest for around 10 mins before serving.

NOTES: most recipes call for blanching the lasagna sheets before baking; this one does not (it’s such a faff!). We get round it by making the ragù a little looser than usual - the extra liquid ensures that the pasta cooks perfectly in the oven while the lasagna is baking.

STORAGE: the lasagna can be stored in the fridge for up to 4 days; cool, place in an airtight container and refrigerate—to reheat, heat in microwave on high until piping hot. The lasagna can also be stored in the freezer for up to 1 month, either baked or unbaked. Baked: cool, place in airtight, freezer-safe containers and freeze; to reheat, thaw in the fridge overnight then reheat in the microwave or oven. Unbaked: assemble the lasagna, cool, cover and freeze; to bake, thaw in the fridge overnight then bake for 1 hr at 200°C/fan 180°C or until the pasta is cooked through the top is browned and crisp around the edges.