Add soaked Rajma and 2 ½ cups of water to a pressure cooker and cook on high until the first whistle. Reduce heat to low and cook for 17 minutes until the rajma is well-cooked. Allow it to depressurize naturally. Drain the rajma thoroughly to remove all water.
Transfer the cooked rajma to a bowl and mash it roughly by hand. Add the paneer, beetroot, carrots, onions, ginger garlic paste, coriander powder, cumin powder, amchur powder, and pav bhaji masala. Mix all ingredients well. Form the mixture into 6-8 patties.
In a separate bowl, combine cornflour, ¼ cup + 2 tablespoons of water, and ¼ teaspoon of salt to create a thin slurry. Place crushed cornflakes on a plate or wide bowl. Dip each patty into the cornflour slurry, then roll it in the crushed cornflakes until fully coated. Transfer the breaded patties to a plate.
Refrigerate the breaded patties for at least 30 minutes to allow the coating to firm up, preventing disintegration during frying.
Preheat your air fryer to 375°F (190°C). Lightly spray the patties with oil.
Air fry the patties for 12-15 minutes, flipping halfway through, until golden brown and crispy.