Combine the garlic, ginger, cayenne, paprika, cumin, salt brown sugar and 2 tbsps of the vinegar in a small bowl and mix well.
Heat the oil in a medium sized frying pan over a medium heat. When hot put in the cinnamon stick and let it sizzle for a few seconds.
Add the onions and stir and fry for five minutes or until softened. Add the paste from the bowl and the garam masala. Stir and fry for 2 mins then add the 150 ml vinegar and the 175 ml water. Stir to mix and bring to a simmer.
Put the egg halves into the pan in a single layer, cut side up and spoon the sauce over them. Cook on a medium heat for about 5 minutes or until the sauce has thickened, spooning the sauce over the eggs frequently. Serve immediately.