Lasagna alla bolognese with spinach pasta sheets

Cook 100 g spinach in a deep pan over medium-high heat with a little pinch of salt, no oil, stirring about 30 seconds until the leaves shrink and release water.

Break the four eggs into a bowl to catch any shell, then blend them with the cooked spinach into a runny cream.

Make a well in 500 g of flour and pour the spinach and egg cream in.

Mix the flour in gradually by hand, then work the dough with the palm pushing forward and back for 10 to 15 minutes, wetting your hands rather than adding water if it is dry.

The dough is ready when it bounces back like a pizza dough. Wrap it in plastic and refrigerate about 30 minutes to build the gluten.

Flour the pasta machine and start at the widest setting, folding the sheet and passing it again to force out the bubbles, then step down one number at a time without skipping.

Stop at number five of nine. Lasagna sheets want to stay thick, not tagliatelle thin.

Cut the sheets to the size of the Pyrex, lay them on kitchen paper separated so they do not stick, dust with flour and keep them covered so they do not dry out.

Mince the pancetta with a knife or the blender.

In a large pot on medium-low, warm about two tablespoons of oil and sweat the pancetta so the fat releases its oil.

Add the onion, celery and carrots and cook the soffritto about 10 minutes with the lid on, stirring every couple of minutes so it does not burn.

Add a splash of red wine to the soffritto, mix, cover and cook two more minutes until the carrots are soft.

Add a touch of extra virgin olive oil and the beef and pork, breaking the meat up and cooking only until the colour turns grey.

Add the rest of the wine and cook about 10 minutes until the alcohol evaporates.

Season with a generous amount of salt and as much pepper as you like, add the tomato paste and spread it through the liquid, then the passata and the peeled tomatoes.

Cook the sauce about four hours, stirring every half hour: three hours with the lid on to keep the liquid in, the last hour uncovered to thicken.

Add salt and pepper again before the final uncovered hour and keep the heat very low so the meat does not stick and burn.

Taste the sauce for salt, then add a splash or two of full cream milk and cook about five minutes without stirring.

For the bechamel, melt 50 g butter gently on medium-low, take the pan off the stove and stir in 50 g flour to a cream.

Add the 500 ml milk a little at a time off the heat, stirring to avoid lumps and scraping the bottom, until it is thick but slightly runny.

Off the stove, add a pinch of nutmeg.

Put one tablespoon of sea salt in boiling water and boil two pasta sheets at a time for about 30 seconds, then move them straight into a bowl of water and ice to stop the cooking.

Rest the cooled sheets on a tray lined with baking paper; they can now be stacked.

Start with bechamel in the Pyrex, then a layer of pasta, then the bolognese - just enough that every bite has meat - then bechamel, then about two tablespoons of Parmigiano Reggiano.

Never put bolognese on the top layer; cover the top with bechamel. Never mix the bechamel and the sauce together.

Cover with foil that does not touch the top and bake at 180 degrees Celsius for 20 minutes.

Uncover, scatter a little Parmigiano Reggiano on top and return to the oven about five minutes so the cheese melts without burning and the edges crisp.

Refoil and return to the oven about 10 minutes at 180 degrees Celsius.

Let it go from hot to warm before cutting, so the slice keeps its shape. Cut with a tomato knife or a bread knife.