Cook the drained chickpeas with the baking soda and 6 cups of water till softened but still holding their shape (30 minutes in my old-school whistling Prestige pressure cooker).
Heat the oil in a deep saucepan over medium heat and add the whole garam masala.
As soon as the tez patta darkens, add the chopped red onion and saute for 10 minutes or so till beginning to brown.
While the onions are browning, add the toasted and cooled spices and the next four ingredients to your spice grinder and powder.
Add the freshly crushed ginger and garlic to the browned onions and saute till the raw aroma is gone.
Add the ground spices, mix in and saute for another minute or two, stirring constantly to make sure nothing scorches.
Strain the tamarind solution into the pan, pushing down hard against the strainer to extract all the tamarind flavour.
Add the jaggery and salt. Mix everything in and bring to a high simmer.
Add the cooked chickpeas with all the pot liquor to the pan, mix in, return to a high simmer and cook uncovered till at a thicker but still easily pourable consistency.
Garnish with the chopped onion, julienned ginger and slit chillies and serve with rice or chapatis or just out of a bowl.
