Take sago in a wide mixing bowl. Rinse it with water once. Soak sago for 2-3 hrs, the water level should be just for the sago to immerse fully, do not add more water.
The water will be fully absorbed, rinse well. If you press a pearl, it should be easily mashable.
Rinse the sago well with water and soak the sago overnight with enough water just to immerse it well. Don't add more else it will become mushy. After the mentioned time if you see the sago must have absorbed the water well and if you press it with your fingers, it will be soft, Set aside.
Dry roast peanuts till golden brown then grind it coarsely just to break it into pieces, don't powder it.
Pressure cook potatoes until soft for 4 whistles, cube them and make it ready. In a pan – heat oil and add the items under 'to temper' and let it splutter. Then add potatoes along with little salt, and give a quick stir. Then add the sago pearls.
Keep cooking and stirring until the sago starts turning transparent. Take care not to mush it up and also make sure it doesn't stick to the bottom. Even if it starts sticking, just keep fluffing it up.
Add crushed peanuts, and sugar at this stage, and give a quick mix.
Add lemon juice and garnish with grated coconut and coriander leaves. Mix well and switch off.
Serve Sabudana Khichdi hot either as a teatime snack or for breakfast!