Heat 3 tablespoons of oil in a heavy-based saucepan and add the carrot, onion and celery. Cook initially at quite a high heat to get the vegetables going for about 5 minutes. Do not allow to colour. Add the garlic, then turn the heat down and continue cooking for another 10 minutes. The base must be totally cooked before you add the mince

Infuse the milk for the cheese sauce by placing the milk, clove-studded shallot, peppercorns and bay leaf in a saucepan together and bring to scalding point. Place a lid on top and set aside

Add the mince to the base and stir around, breaking up the meat. Cook on a high heat until all the meat has lost its raw colour. Now add the tin of tomatoes (if they’re whole peeled tomatoes then be sure to break them up), along with the bay leaf and plenty of seasoning. (If you happen to have the dregs of a bottle of white wine knocking around, then feel free to add a generous glass to the proceedings. If not then so be it…)

Allow to blip blip away at a very gentle simmer with the lid on askew for at least an hour. Stir every now and then. Taste and adjust the seasoning

Preheat an 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. If there is a lot of flesh (I find marrows can be quite variable), then scoop out some flesh, leaving a 1 cm border. If it isn’t so fleshy and there is only about 1cm of flesh all around then not to worry, leave the marrow as it is

Drizzle 2 tbsps of the 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 for now

Finish making the cheese sauce by melting the butter over a 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, switch back to a wooden spoon and stir constantly until the sauce has thickened and just come to a simmer. Turn off the heat. Add 120g of the grated Parmesan and season with salt, pepper and the nutmeg. Lastly, stir in the egg

Time to assemble the marrow. Fill each marrow half with meat sauce until it comes to just before the top. You may have some meat sauce left over – this will do perfectly for a separate meal of spag bol. 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