¼ cup Spicy Ketchup
1 tbsp tamarind concentrate
1 tsp brown sugar
1 tbsp water, or more as needed
1 large red onion, thinly sliced (2 cups)
1 cup chickpea flour
½ tsp cumin seeds
½ tsp ground turmeric
¼ tsp cayenne
½ tsp salt
1 tsp minced ginger
1 tsp minced fresh green chili with the seeds (serrano, Jalapeno, or Thai)
2/3-3/4 cup water
Neutral oil, for deep frying
Combine all the tamarind chutney ingredients in a bowl. Set aside.
Make the pakora batter by combining all the dry ingredients, ginger, and green chili in a medium-sized bowl. Stir in 2/3 cup water, or more as needed to make a thick but pourable batter that coats a spoon.
Fold the onions into the batter and set aside for 2-3 minutes to allow the onions to release their water.
Heat 2-inches of oil in a 2 or 3-quart saucepan to 350F(180C).
Using a soup spoon, take a generous spoonful of pakora mixture and gently push it into the oil, working close to the oil to avoid splashing. Cook the pakora until they turn golden on the underside, which takes about 1 minute, then carefully turn and fry until golden on the other side. Transfer all the bits to a paper-lined tray and repeat with the remaining batter.
Serve immediately with the tamarind chutney.