Chop the crushed garlic with a quarter teaspoon of fine sea salt with a large cook’s knife to make a smooth paste. Thoroughly combine with the yoghurt.
For the Potatoes
Preheat your oven to 375 F / 190 C/ Gas Mark 5. Place the potatoes in a pan of cold salted water, bring to the boil and simmer for five minutes. Carefully drain and then toss in the spices and season generously, then tip into a baking tray and drizzle with lots of oil. Place in the hot oven and cook for twenty-five minutes.
For the Lamb
While the potatoes are roasting, pat the lamb dry and season generously. Heat the oil in a heavy-bottomed frying pan and carefully place the lamb, fat side down, and sear until the fat is rendered and golden brown. Turn the lamb over and sear the other side for three to four minutes.
Carefully remove the potatoes from the oven. Turn them over and add the seared lamb. Return to the oven and cook for a further twenty minutes. Remove the lamb, wrap it in foil and a tea towel and allow it to rest for five to ten minutes. Keep the potatoes warm in the oven at a reduced temperature.
For the Vegetables
Prepare the asparagus by trimming off the bottom couple of centimetres and cut in half.
Bring a pan of salted water to the boil and add the asparagus and peas for one minute. Strain and refresh in ice-cold water, then drain and set aside.
Heat the olive oil and butter in a large heavy-bottomed frying pan over a medium-high heat and add the courgettes. As the courgettes start to turn golden brown, add the asparagus and peas and cook for three to four minutes to cook through. Remove from the heat and season.
To serve, slice the lamb alongside each bone to divide up the racks into cutlets. Spoon the yoghurt into four bowls and top with the roasted potatoes. Sprinkle a little of the flavoured oil over each. Top with the Spring vegetables and the lamb. Garnish with pea shoots.