First, in a mortar and pestle, grind the ginger, seeds and ginger to make a rough paste.
Bring this over to a bowl containing the cooked onions and mix together along with the flour, spices, oil and lemon juice. Bring the dough together with a little water - bear in mind it needs to be quite dry.
On a lined baking tray put 6 tablespoons of the mixture and pat down slightly. Press a piece of chicken into each one and cover with more bhaji mix, then bake at 360°F/180°C for 35 minutes, basting occasionally with oil, until they are golden brown and crisp. Serve with mango chutney and fresh coriander.