Cut the legs from the carcasses and then remove the breasts - you may want to ask your butcher to do this for you. Mix the yoghurt with half the garlic, the ground cumin and coriander and ¼ teaspoon salt. Use this to generously coat the breasts and then place them, covered, in the fridge for 12-36 hours.
Make the relish. Heat up a medium-sized pot, add 1 Tablespoon cooking oil, then sauté the onion, ginger and the remaining garlic until they begin to caramelise over a moderate heat, stirring frequently. Stir in the star anise, chilli flakes and half the sesame seeds and sauté another minute. Add the plums, umeshu liqueur and sugar and bring to a boil, then put the lid on the pot and cook for 5 minutes. Take the lid off, give it a stir and increase the heat and cook until the liquid has reduced by three-quarters. Add the vinegar, bring back to the boil then take off the heat, taste for seasoning and spoon into a clean container and seal while hot. Once cooled this will keep in the fridge for a week.
Make the rösti. Preheat the oven to 160°C. Grate the potatoes coarsely then squeeze out any excess moisture between your hands. Mix with the ground quinoa, poppy seeds, the remaining sesame seeds, the rosemary, 2 teaspoons flaky salt and some freshly ground black pepper. Line a baking tray with parchment and lightly oil it. Using a 10-cm round cookie cutter, or something similar, press a quarter of the mixture in firmly to give you a fat disc. Use the remaining mixture in the same way to give you four rostis. Drizzle a little oil over each one then bake for 20-30 minutes, until they’re beginning to turn golden. Leave to cool on the tray then remove, and turn the oven to 200°C.
Mix the curry powder in a medium bowl with 1 Tablespoon cooking oil and a little salt then add the cauliflower and toss it all together. Lay the cauliflower on the same tray you baked the rosti on and cook until the florets turn golden - around 6-10 minutes. Remove from the oven.
To cook the pigeon, wipe off excess yoghurt marinade and discard it. Place an ovenproof pan large enough to hold all eight breasts over a moderate-high heat and then add the butter and 1 Tablespoon vegetable oil. Once the butter has been sizzling for 30 seconds place the breasts in skin-side down and cook for 2 minutes, before turning over and cooking for 1 minute. Place in the oven and cook for a further 2 minutes then take out and leave to rest in the pan, in a warm place, for 2 minutes. At this point they will be between medium-rare and medium - you may prefer to cook a little less or more.
To cook the rösti, heat up 1 cm of vegetable oil in a deep-sided pan (or you can deep-fry them) and when it gets to 180°C place the rösti in, as many as you can fit comfortably and cook on both sides until golden and crunchy. Take from the oil, drain of excess oil and keep warm while you cook the remainder.