Ideal for making beforehand and freezing, freeze in a polybox uncooked, interleaved with greasproof paper. Thaw overnight in the fridge and cook as in recipe.
- First melt the butter in a pan then fry the onions gently for 5 minutes
- Transfer to a bowl and mix in the remaining ingredients
- Divide into 24 and shape into burgers
- cook on a well heated barbecue for 15 minutes