Preheat the oven to 170°C.
Mix salt, rosemary, and thyme together and rub the mixture onto the lamb shoulder.
Let the lamb sit for one to four hours.
Rinse the salt off the lamb, pat it dry, and rub with olive oil.
Place sliced onions in a roasting tin, top with lamb, and cover with foil.
Roast for two hours, then remove foil and roast for 1-2 more hours until tender.
Remove the lamb from the tray and let it rest.
Deglaze the roasting tray with white wine on the hob and reduce by half.
Stir in flour for two minutes, add stock, and simmer for three minutes.
Strain the gravy and season with salt and pepper.
Boil the potatoes in salted water for five minutes.
Preheat the beef dripping in a roasting tray in the oven.
Drain potatoes and shake them to roughen the edges.
Coat potatoes in the hot fat, sprinkle with salt, and roast for 30 minutes.
Turn the potatoes and roast for another 30 minutes until crisp.
Sauté spring greens in butter for three minutes, add water, and steam until wilted.
Season the greens with salt and pepper.
Heat vinegar and sugar until simmering, then pour over chopped mint to make sauce.
Pull the lamb meat from the bone and serve with potatoes, greens, mint sauce, and gravy.