Preheat your oven to 180 degrees and spray a baking tray liberally with low calorie cooking spray.
Put the onions, sweet potato, spices, and eggs into a bowl and add a generous pinch of salt and pepper. Mix well.
Using your hands, divide the mixture into 8 bhajis and place them on the baking tray, being careful to ensure that they don't touch each other. At this stage, you might feel a little sceptical that they'll stay together and won't fall apart - don't worry, they'll be fine!
Spray liberally with low calorie cooking spray.
Bake in the oven for 25 minutes, or until they're nicely crisped. Carefully turn the bhajis over halfway through cooking, and spraying again with the low calorie cooking spray.
Decorate with the fresh coriander, serve, and enjoy!