In a mixer jar, grind 1 cup of chavanu into a coarse powder. Set aside.
In the same jar, add 2-3 green chilies, 1-inch piece of ginger, 4-5 garlic cloves, and ½ tsp cumin seeds. Grind into a coarse paste without adding water.
Add 1 large tomato and 1 tsp of sugar to the mixer jar. Grind until smooth and set aside.
In a mixing bowl, combine the ground chavanu, the chili-ginger-garlic paste, 1 tbsp white sesame seeds, ½ tsp turmeric powder, a pinch of hing, 1 tsp Kashmiri red chili powder, 1 tsp coriander powder, ½ tsp garam masala, ½ tsp dry mango powder, ½ tsp black salt, a pinch of regular salt, the ground tomato mixture, and some chopped coriander leaves. Mix well to form the stuffing.
Take two potato slices of the same size and stuff the prepared masala between them.
Dip the stuffed potato slices into the besan batter, ensuring an even coating. Remove any excess batter.
Heat oil in a pan. Fry the bhajiya on medium heat until golden and crispy on both sides.
The Batata Bhajiya is ready. Serve hot with dahi chutney.