Pre-heat the oven to 200ºC. Spray a baking sheet with low calorie cooking spray.
Spray a frying pan with low calorie cooking spray and sauté the onions over a medium heat for 5 minutes, until soft. Allow to cool slightly.
Place the remaining ingredients in a large bowl and mix until well combined.
Check the seasoning by cooking a small piece in a frying pan and add some salt and pepper if required.
Divide into 18 equal pieces and roll into balls.
Place on the prepared baking sheet and spray with low calorie cooking spray.
Cook in the oven for 15-18 minutes and serve as part of a Christmas roast.