Clean and rinse the sabudana 3-4 times and soak it in 1 cup of water overnight or at least 5-6 hours.
After 5 hours, check if the sabudana has soaked well enough and softened by pressing some pearls. If it is mashed easily, it means it is perfectly soaked. If you feel some hardness in the centre of the pearls, then add a few tablespoons of water to the bowl. Cover and leave to soak for another 30 minutes.
Strain the sabudana in a colander and keep it aside.
Take a big mixing bowl and add boiled grated potatoes, crushed roasted peanuts, ginger, green chilli, coriander leaves, curry leaves, roasted cumin powder, black pepper powder, lemon juice, sugar and sendha namak. Mix it well.
Combine and mash the mixture well with your hands, and adjust the spices and seasoning according to your taste. Divide the mixture equally, wet your hands and roll it into balls. Keep it aside.
Heat the waffle maker and brush with ghee or peanut oil.
Now, add the prepared ball to the waffle maker. Press it down gently and evenly from all sides. Brush it with ghee on the top of the waffles.
Close the waffle maker. Let it cook for 8-10 minutes, until crisp and golden. Take it out gently using a spatula. Repeat the same process to make all the sabudana waffles.
Sabudana waffles are ready to serve. Serve it hot with green chutney or tomato ketchup.