Slow-cooked Lamb Shoulder Lasagna

Preheat the oven to 160°C/325°F/gas mark 2. Place the oil in a large casserole over a medium heat. Add the meat in batches and fry until it is nicely golden brown all over. Remove with a slotted spoon and set aside. Reduce the heat and throw in the onions, carrots and celery. Cook for 15 minutes or until the vegetables have softened and gone slightly golden. Add the garlic for the last 2 minutes of cooking.

Stir in the tomato purée and cook for 1 minute. Add the herbs, wine, stock and tomatoes. Return the meat and all its juices to the pan. Give it a good stir, then cover and place in the oven.You want the meat to be really soft and the sauce to thicken and become rich. After 2 hours remove the casserole from the oven and leave it to rest for 10 minutes, then go to the meat with two forks and shred it to bits. The meat should break up as you squish it a little with the back of a wooden spoon.

To make the white sauce, melt the butter in a pan over a low to medium heat. Stir in the flour and cook for 1 minute. Take the pan off the heat and gradually whisk in the milk, little by little, stirring like crazy until combined and smooth. Stir in the chopped mozzarella and a few gratings of fresh nutmeg. Season to taste and set aside.

Drop the lasagna sheets into a large pot of boiling water for 1 minute then drain them. Drizzle some olive oil on to the sheets to keep them separate. To build the lasagna, spread a layer of meat sauce over the bottom of a large lasagna dish. Spoon over a little of the white sauce. (The ratio should be about two-thirds meat to one-third white sauce.) Repeat 3 or 4 times, depending on the size of the dish, then spoon over the remaining white sauce to cover completely. Sprinkle with grated Parmesan. Bake for 45–50 minutes until the top is golden.