Boil the potatoes till soft and keep aside(I boil them in a cooker giving it one whistle on medium flame)
Immediately after keeping all the ingredients ready, Wash the Poha in a big fine strainer till all the water runs clear and let it stay in the strainer
In a Kadai, heat the oil on medium flame.
Once the oil is hot, add the mustard seeds and cumin seeds(if using) and let it crackle.
As the mustard starts to crackle, add the the curry leaves and let it cook for 1 minute
Then add the onions,tomatoes(if using) and green chillies and stir it well
Cover it with a lid and let it cook until the onions cook well
Add the roasted peanuts, turmeric powder, boiled potatoes, sugar, salt, juice of half the lemon and give it a quick stir
Then add the Poha and coriander leaves and gently mix it with a flat spatula or spoon until all the rice flakes are covered in turmeric powder and turn yellow. (If you think the poha is too light in colour, you can add more turmeric powder)Note:-Don't be in a hurry to rigorously stir the poha or else the flakes may break down and the poha may turn sticky(unless you like sticky poha. Well, some do like it sticky :) ) Taste and check if you require more salt, sugar or lemon juice. If you do, then add it at this stage
Garnish with fresh Coriander and Roasted peanuts and enjoy a bowl of Hot Poha/Fova/Flattened Rice with a nice Hot cup of Tea :)