Soak the porcini and the quartered figs in the port and allow to infuse overnight. Clean the lamb rack from all bones, season and seal well from all sides, than finish in the oven. Add a knob of butter and the sugar in the same pan, and caramelize, add the port with the figs and porcini than pour in the stock and simmer. Peel the celeriac and dice in small cubes, sauté with the chopped garlic and thyme in butter until lightly browned than add 4 tbsp of warm vegetable stock cover and simmer. Use a fork to mash once it’s soft enough, season and remove from heat. Chop the spring onion and saute in butter with the mixed spice, add the spinach and stir continuously. Finish the lamb in the oven, ideally until cooked medium to rare, than allow to rest and carve.