Step 1: Prepare the Potato Filling

1. Boil the potatoes: Peel and mash the potatoes after boiling them in a pressure cooker or pot until soft. Make sure there are no lumps in the mashed potatoes.

2. Heat oil in a pan: Add mustard seeds and cumin seeds. Let them splutter for a few seconds.

3. Add chopped green chilies, ginger, and curry leaves to the pan and sauté for 1-2 minutes until the aroma releases.

4. Spice the mixture: Add turmeric powder, red chili powder, and garam masala (if using). Stir well.

5. Add the mashed potatoes to the pan, mixing everything thoroughly. Cook for 3-4 minutes so the spices blend well with the potatoes.

6. Add amchur powder or lemon juice and salt to taste. Stir in the chopped coriander leaves. Let the mixture cool for 15-20 minutes.

Step 2: Shape the Vada

1. Once the potato mixture is cool enough to handle, shape it into small balls (about the size of a golf ball). Make sure the balls are smooth and even.

Step 3: Prepare the Batter

1. In a separate bowl, combine the besan (chickpea flour) with rice flour (for crunch), baking soda, turmeric powder, red chili powder, and salt.

2. Gradually add water and whisk the mixture into a smooth, thick batter. The batter should be thick enough to coat the vadas completely, but not too runny. You should be able to dip the shaped potato balls into the batter without it dripping off easily.

Step 4: Heat the Oil

1. Heat oil in a deep frying pan or kadhai. The oil should be hot enough to fry the vadas, but not smoking. To test, drop a small amount of batter into the oil; if it rises to the surface immediately, the oil is ready.

Step 5: Coat and Fry the Vadas

1. Dip each potato ball into the batter, ensuring it’s fully coated.

2. Carefully drop the coated vadas into the hot oil, one by one, avoiding overcrowding the pan. Fry them on medium heat to ensure even cooking.

3. Fry the vadas until they turn golden brown and crispy on all sides, about 4-5 minutes.

4. Remove the vadas from the oil using a slotted spoon and place them on a paper towel to absorb any excess oil.

Step 6: Serve

1. Serve the Aloo Vadas hot with tamarind chutney, green chutney, or in a vada pav with a slice of pav (bread roll) and a few fried green chilies for a classic Mumbai-style snack.