Cut aubergines lengthwise and score the skin side, 4-5 times.
Place aubergines with flesh side down in a large greased non-stick tray. Lightly grease the skin of the aubergines.
Cook the aubergines under hot grill for about 20-30 minutes until the skin is crinkled and can be easily peeled off. Whole aubergines can also be roasted directly on the gas flame until the skin chars and crinkles.
Leave to one side for 10 minutes before peeling the charred skin off the flesh.
Chop the onions and garlic.
Discard the scorched skin and chop up the cooked pulp.
Heat oil in a pan and add mustard, ajwain and fenugreek seeds, in that order. Add asafoetida when seeds start to splutter and then quickly add the garlic and the onions. Fry on a medium heat until translucent.
Add chilli and ginger, and fry for 20 seconds and next add the chopped aubergine pulp. Add the dhana-jeeru. Roast for a minute more.
Add finely chopped ripe tomatoes (fresh or frozen). See the 'Top Cooking Tips' page, point 5 for frozen tomatoes.
Add salt to taste and sugar if using, mix well.
The orro should have a chunky consistency with a bite.
Garnish with the chopped coriander before serving.