Put the yoghurt in a large bowl, add the coriander, turmeric, and chilli powder and, season with salt. Stir well and set aside.
Heat 2 tablespoons of the oil in a heavy-based pan over medium heat, add the mustard seeds, kalonji seeds, and fennel seeds and, stir-fry for about 1 minute, or until the seeds start to splutter.
Add the dried red chillies, and stir-fry for a further 2 minutes, or until the chillies turn a shade darker.
Add the paneer together with the amchoor and, stir-fry for about 5 minutes, or until all the moisture has evaporated. Season with salt, then remove from the heat and stir in the yoghurt mixture.
Pour the remaining mustard oil on top and garnish it with green chillies.