For the roast lamb jus, heat the olive oil in a large pan over a medium heat. Add the lamb bones and fry for 4-5 minutes, or until browned all over. Add the onion, carrots, celery and leek and fry for 3-4 minutes, or until golden-brown

Add the garlic, bouquet garni, wine and stock, stir well and bring to the boil. Skim off any foam that rises to the surface using a skimmer, then reduce the heat to a simmer. Simmer over a low to medium heat for up to four hours, skimming off the foam from time to time

When the stock has simmered for four hours, strain into a large clean pan and boil until reduced to a syrupy consistency. Set aside until needed

For the lamb with lemon and mint stuffing, mix together the lamb mince, lemon zest and mint in a bowl until well combined. Season to taste with salt and freshly ground black pepper

Preheat the oven to 200ºC/Gas mark 6. Remove the loins from the saddle, reserving the rectangle of fat. Lay the two loins side by side on the rectangle of fat and spread the lemon, mint and mince stuffing mixture over the loins. Bring the edges of the fat up over the lamb loins and stuffing then tie securely with string to make a neat parcel

Heat the oil and butter in a frying pan over a medium heat. When the butter is foaming, add the lamb parcel and fry for 4-5 minutes, turning occasionally, until golden-brown all over

Place the browned lamb parcel onto a wire rack, then transfer the wire rack to a roasting tin. Season the lamb parcel with salt and freshly ground black pepper

Roast in the oven for 15-20 minutes (for pink meat) or for up to 30 minutes if you prefer your lamb medium to well done. Remove from the oven, cover with aluminium foil and set aside to rest in a warm place

For the ratatouille, mix together the onion, aubergine, peppers, courgette, garlic and olive oil until well combined. Season to taste with salt and freshly ground black pepper. Transfer the mixture to a roasting tray and roast in the oven for 10-12 minutes, or until softened and beginning to turn golden-brown

Add the cherry tomatoes and basil and stir well to combine. Return the mixture to the oven and cook for a further 20 minutes, or until the vegetables are just tender. Season to taste with salt and freshly ground black pepper

For the olive oil mash, bring the milk, garlic, thyme and rosemary to the boil in a pan stirring well. Remove the pan from the heat and cover. Set aside for 10-15 minutes to allow the flavours to infuse, then strain the liquid

In a separate pan, boil the potatoes in salted water for 10-15 minutes or until tender. Drain well and return to the heat for a few seconds to drive off any excess moisture. Mash using a potato masher or ricer

In a separate pan, bring the strained milk mixture and olive oil to the boil slowly. When the mixture is boiling, pour it over the mashed potatoes a little at a time, whisking vigorously until all of the liquid has been incorporated into the mashed potatoes and the mixture is smooth

To serve, carve the roast lamb into thick slices. Spoon the ratatouille into the centre of four serving plates and spoon a portion of olive oil mash alongside. Place the lamb slices on top of the ratatouille and drizzle over the lamb jus