Place the aubergines on a baking tray, and prick the skin a few times with a fork. Bake at 200°C (Gas Mark 6 / 400°F) for around an hour, until soft. Leave the oven on.
When the aubergines are soft, cut then in half lengthwise, and allow them to cool for a few minutes. Scoop the flesh from the skin with a spoon, and mash the flesh thoroughly with a fork (or chop it thoroughly with a knife, if easier). Add the mashed flesh to a large bowl (discard the skins).
If using Veetee instant rice, cook it for a couple of minutes in the microwave to soften it up, then add it to the bowl with the aubergine. Add the chopped chives, beaten egg, and a generous amount of salt and pepper, and mix thoroughly. Mash the rice a little to help the mixture to stick together.
Lightly grease a baking tray, and spread the breadcrumbs out on a small plate.
With clean hands, take a small amount of the rice mixture (maybe 3/4 of a tablespoon or so), and press it into the palm of your hand. Place a small piece of mozzarella on top, and then some more of the rice mixture. Shape into a ball surrounding the mozzarella, and squeeze tightly to help it to hold together.
Roll the ball in the breadcrumbs, and place on the baking tray while you repeat with the remaining ingredients - aim to make around 10-12 balls in total.
When you have used up all of the rice mixture and mozzarella, spray the rice balls lightly with oil, and bake for around 30 minutes, until the breadcrumbs are golden brown and crispy.