Peel the potatoes and slice them into thin rounds using a knife or mandoline slicer. Place the potato slices in a bowl of cold water until you’re ready to use them. This step helps remove excess starch and prevents browning.
In a mixing bowl, add besan (gram flour), rice flour, ginger, ajwain, red chili powder, turmeric powder, garam masala, salt, and baking soda (optional). Mix well to combine the dry ingredients.
Gradually add water, a little at a time, while whisking to achieve a smooth batter with a medium-thick consistency.
The batter should be neither too thick nor too thin; it should coat the potato slices evenly. Whisk the batter for at least 2 minutes to ensure it is light, fluffy, and airy.
Heat oil in a wide, deep kadai on a medium-high flame.
Once the oil is hot enough, add a few potato slices to the batter, gently toss them to coat evenly, shake off any excess batter, and carefully slide each coated slice into the oil. Avoid overcrowding the pan.
Fry the bajjis until they turn crispy and golden brown on both sides.
Once done, use a slotted spoon to remove bajjis from the oil and place them on a paper napkin to absorb any excess oil.
Potato bajjis are ready. Sprinkle some chaat masala for a tangy touch. Serve immediately.