Heat 3 tablespoons of oil to a heavy-based saucepan, add the carrot, onion and celery. Cook for about 5 minutes. Add the garlic, then turn the heat down and cook for another 10 minutes.
Infuse the milk for the cheese sauce by placing the milk, shallot, peppercorns and 1 bay leaf in a saucepan and bring to scalding point. Place a lid on top and set aside
Add the mince to the vegetables and stir, breaking up the meat. Cook on a high heat until all the meat is cooked. Add the tin of tomatoes, 1 bay leaf and plenty of salt and pepper.
Set the sauce to a very gentle simmer for at least an hour. Stir every now and then.
Preheat the oven to 175°C/gas mark 4. Wash the marrow, trim the ends off and slice it in half lengthways. Scoop out the seeds and fluff. Scoop out some flesh, leaving a 1 cm border.
Drizzle 2 tbsps of oil over the marrow and place on a baking tray and then into the oven. Bake for about 30 minutes until the flesh is only just cooked. Remove and set aside.
Finish making the cheese sauce by melting the butter over low heat in a saucepan and then add the flour. Cook for at least two minutes, stirring all the while. Strain the milk and add it all at once, whisking vigorously.
Once everything has combined and is smooth, stir until the sauce has thickened and just come to a simmer. Turn off the heat. Add 120g of grated Parmesan and season with salt and pepper. Lastly, stir in the egg
Fill each marrow half with meat sauce until it comes to just before the top.
Pour over the bechamel until it is generously covered. Sprinkle with the remaining Parmesan.
Place in the oven and cook for half an hour or until golden brown
[addedItemsTotalItemCount] item[s] added to Shopping Basket