Mix all the daals in a bowl. Wash 4-5 times in cold water or until the water runs clear. Drain well.
Place the Instant Pot on sauté mode. Add the ghee, onions and salt. Cook, stirring all the time until the onions have browned, about 10 minutes. Add the ginger, tomatoes, turmeric and black pepper. Mix well and cook for a further minute.
Tip the drained daal into the pot, along with the baking soda (this well help it cook quickly and evenly) and stir well. Pour in the water and bring to the boil.
Place the lid on the Instant Pot or pressure cooker. Cook on high pressure for 20 minutes. This will be approximately 6-7 whistles on a traditional pressure cooker. If you're using the latter, keep the heat at a medium level to prevent the daal settling and burning at the base of the pan.
After 20 minutes, carefully release the pressure from the pan and remove the lid. Add the garam masala and chilli powder. Season with salt to taste, if required. Whisk the daal with a hand-held whisk for 90 seconds, until it's creamy, but still coarse in texture. Beating the daal gives it a wonderful texture. Keep the daal over a low heat while you prepare the tadka.
In a separate small pan, heat the ghee for the tadka. Add the cumin seeds, garlic, green chillies and dried red chillies. Cook, stirring all the time until the garlic has browned very slightly and the chillies have become blistered on the outside.
Immediately pour the sizzling tadka over the hot daal. Take care not to splash yourself while you do this! Sprinkle with crispy fried onions and fresh coriander. Serve piping hot with rice and roti, naan or paratha.