Place the whole potatoes in a pot of water and boil until a knife slides through them easily.

Peel and mash the boiled potatoes, then mix in the green chili, coriander leaves, ginger, turmeric, red chili powder, chaat masala, and salt until evenly combined.

Whisk the gram flour with water and the baking soda into a smooth, medium-thick batter that coats the back of a spoon.

Let the batter sit uncovered so the gram flour fully hydrates and the baking soda activates.

Spread a generous layer of the potato filling on one bread slice, top with a second slice, and press firmly, then trim the edges and cut each sandwich diagonally into triangles.

Heat the vegetable oil in a kadai over medium-high heat until a drop of batter sizzles and rises to the surface immediately.

Dip each bread triangle fully in the besan batter to coat all sides, then slide it into the hot oil and fry, turning occasionally, until golden brown and crisp.

Lift the fried pieces out with a slotted spoon onto paper towels to drain, then repeat the dipping and frying process with the remaining bread triangles.

Let the fried pakoras sit for a few minutes so the coating firms up before serving.