1. Add meat to large bowl.
2. Add the breadcrumbs, salt, celery salt, pepper, Worcester sauce and egg.
3. Mix by hand. Be careful not to over mix as it will make burgers tough.
4. Form into patties of your preferred size and brush with oil, cover lightly with cling film and chill ready for use.
5. Add slug of vegetable oil to pan and once heated add finely sliced onions along with sugar.
6. Cook on a low heat mixing from time to time until they brown and caramelize.
7. Remove burgers from fridge and cook for approximately 5mins each side on a moderate heat, barbecue or griddle.
8. When you have 'flipped' burgers add sliced cheese, a couple of minutes into cooking so that it will soften but not melt completely.
9. Serve burgers on toasted buns or bread rolls with some leaves, chilli jam and caramelized onions.

Gaynor's Tip: These burgers are really easy to make in advance in volume.

Source: Resident Food Farmison Blogger Gaynor Mairs