To prepare the burgers: Heat a little oil in a frying pan. Add the onion and cook for 4-5 minutes until softened but not browned. Remove from the heat and allow to cool. Place the mince in a large bowl. Take the skin off the sausages and crumble the meat into the bowl with the pork. Add the cooled onion, coriander leaves, salt and pepper.
To cook: Divide the mixture into four burgers. Heat a grill pan or barbecue to medium. Add the burgers and cook for 3-4 minutes on each side.
Serving Suggestions
To serve: Cut the buns in half and toast the cut side. Put a little blue cheese dressing on the lower half of each bun. Top with two slices of tomato followed by some lettuce, then the burger. Spoon on a little more dressing. Rest the top of the bun against the side and serve with potato wedges.