For the samosa dough, place the flour salt, ajwan and ghee into a food processor and process until just incorporated, with some small chunks of ghee still remaining.
Transfer to a bowl with the water and mix with hands until dough just comes together as a soft, pliable dough, with some small streaks of ghee still remaining. Wrap in cling film and set aside in the fridge to rest for at least 45 minutes.
For the potato dilling, heat 1 tablespoon of the oil in a frypan over low-medium heat, add the shallots and sauté until softened. Add ginger, garlic, Indian bay leaf, chillies, both cardamoms and mustard seeds and toast until fragrant. Add the toor dhal and toast until fragrant, stirring occasionally.
Add the cumin, ground coriander, garam masala and turmeric and toast for a further 1 minute. Add potatoes and stir to coat. Add curry leaves and cook, stirring, for a further 1-2 minutes.
Add a little water and stir through, then cook until the potatoes are completely soft, about 2 minutes. Drizzle with a little mustard oil and stir to coat. Adjust spices to taste then remove from the heat. Add cooked black dhal, lemon juice and salt and stir to combine.
Transfer potato mixture to a bowl, then add a little water to the frypan and scrape remaining juices into the bowl of potato mixture. Set aside to cool.
For the mango chutney, combine sugar and water in a small saucepan over medium heat and cook until the sugar has dissolved. Remove from the heat.
Place the spices into a small frypan over medium heat and toast until fragrant, add mango and cook down until the mango has softened and collapsed, about 10 minutes.
Add the sugar syrup to the mango and cook, stirring until reduced to a jam-like consistency. Remove from the heat and set aside.
For the coriander chutney, blanch the coriander leaves in boiling water then refresh in iced water. Drain well to remove excess water.
Place the blanched coriander leaves, ginger and garlic into a small food processor. Add salt, young coconut flesh and coconut water and blitz until smooth.
Heat the mustard oil in a frypan. Add green cardamom seeds, mustard seeds, chilli and curry leaves and toast until fragrant. Remove from pan and allow to cool slightly.
Add toasted spices to the food processor of puréed coriander and process until smooth. Set aside until needed.
Fill and heat a deep fryer to 180C in preparation for cooking the samosas.
Lightly flour a clean work surface. Divide the rested samosa dough into 4 portions. Roll into logs then cut each log into 6 portions.
Roll the log portions out flat to 1mm thick, then use an 8cm round cutter to cut into discs. Cut each disc in half to make semi circles.
Remove and discard the whole spices from the potato filling.
Spoon about 1 tablespoon of the potato filling into the centre of each pastry semi circle. Brush the edges of the pastry with a little water. Fold the pastry over to enclose the filling and make a triangle shape. Press the edges of the pastry with a fork to seal.
Working in batches, add the samosas to the deep fryer set at 180C and cook until golden brown and crisp, about 3-4 minutes. Remove from fryer and drain on paper towel.
For the dressing, place all ingredients in a small bowl and stir to combine.
To serve, smear coriander chutney in a circle onto the serving plate. Spoon some plain yoghurt in a circle through the coriander chutney. Top with samosas. Drizzle the dressing around the plate. Spoon some mango chutney onto the side of the plate. Finish with fresh coriander leaves.