For the pakora, mix together all of the ingredients apart from the gram flour and vegetable oil. Season with salt, then stir in half the flour. Continue to mix in the gram flour until the batter is the consistency of thick double cream and clings to the vegetables.
Fill a deep-fat fryer with vegetable oil and preheat to 180C. (CAUTION: hot oil can be dangerous. Do not leave unattended.)
When ready to fry, pick up small clumps of the batter-clad vegetables and carefully lower them into the hot oil. Fry for about 3 minutes, or until crisp and golden. Remove the pakora using a slotted spoon and drain on a plate lined with kitchen roll. Keep the pakora warm in a low oven while you make the sauce.
For the sauce, whisk the yoghurt, gram flour, salt, 200ml/7fl oz water and turmeric together then tip in to a large saucepan and warm through over a very low heat, stirring regularly.
Keeping an eye on the yoghurt, heat the ghee in a separate frying pan and add all the spices and the garlic. Heat very gently for about 10 minutes, to allow the flavours to infuse.
Stir the infused ghee (including the spices and garlic) into the warmed, spiced yoghurt. Finish with a good squeeze of lemon juice.
Serve up the yoghurt sauce atop cooked basmati rice and dot over the pakora, finishing the whole thing off with a generous sprinkle of chopped coriander.